Topical bioadhesive formulations

ABSTRACT

The present invention relates to topical bioadhesive formulations comprising low viscosity, non-liquid crystalline, mixtures of: 
     a) at least one neutral diacyl lipid and/or at least one tocopherol;
 
b) at least one phospholipid;
 
c) at least one biocompatible, oxygen containing, low viscosity organic solvent;
 
wherein at least one bioactive agent is dissolved or dispersed in the low viscosity mixture and wherein the pre-formulation forms, or is capable of forming, at least one liquid crystalline phase structure upon contact with an aqueous fluid. The invention additionally relates to a method of delivery of an active agent comprising administration of a preformulation of the invention, a method of treatment comprising administration of a preformulation of the invention and the use of a preformulation of the invention in a method for the manufacture of a medicament.

The present invention relates to formulation precursors(pre-formulations) for the in situ generation of controlled releaselipid compositions. In particular, the invention relates topre-formulations in the form of low viscosity mixtures (such asmolecular solutions) of amphiphilic components and at least onebioactive agent which undergo at least one phase transition uponexposure to aqueous fluids, such as body fluids, thereby forming abioadhesive matrix.

Many bioactive agents including pharmaceuticals, nutrients, vitamins andso forth have a “functional window”. That is to say that there is arange of concentrations over which these agents can be observed toprovide some biological effect. Where the concentration in theappropriate part of the body (e.g. locally or as demonstrated by serumconcentration) falls below a certain level, no beneficial effect can beattributed to the agent. Similarly, there is generally an upperconcentration level above which no further benefit is derived byincreasing the concentration. In some cases increasing the concentrationabove a particular level results in undesirable or even dangerouseffects.

Some bioactive agents have a long biological half-life and/or a widefunctional window and thus may be administered occasionally, maintaininga functional biological concentration over a substantial period of time(e.g. 6 hours to several days). In other cases the rate of clearance ishigh and/or the functional window is narrow and thus to maintain abiological concentration within this window regular (or even continuous)doses of a small amount are required. This can be particularly difficultwhere non-oral routes of administration (e.g. parenteral administration)are desirable. Furthermore, in some circumstances, such as in thefitting of implants (e.g. joint replacements or oral implants) the areaof desired action may not remain accessible for repeated administration.In such cases a single administration must provide active agent at atherapeutic level over the whole period during which activity is needed.

Similarly, where the effect of a bioactive agent is required locally, itmay be difficulty or undesirable to administer sufficient of that agentto achieve the effective level throughout the body of the subject. Thismay be due to undesirable effects of the agent itself (e.g. for steroidanti-inflammatory), or may be because the agent is used to locallycounter an undesirable feature of a systemic treatment (such aschemotherapy) but would undermine that primary treatment if usedbroadly.

A major difficulty with topically applied compositions is, however,their duration of action. These composition are, by their nature,applied to body surfaces which may be prone to abrasion, washing andflushing with bodily or applied fluids, such as tears, sweat or mucous.A particularly difficult situation for the use of topical preparationsis in body cavities, such as the GI tract. This is because such cavitiesare typically coated in a mucous membrane which is non-adherent andturned over rapidly. In addition, thick, viscous preparations can bedifficult to apply effectively to the mouth/throat or rectally to thelower GI tract and are difficult to manufacture due to high viscositypreventing sterile filtration. Existing compositions, however, aretypically either low viscosity and short-lived or longer lived at theprice of high viscosity. Furthermore, existing topical compositions areoften capable of containing only a low level of active agent, due topoor compatibility between the base composition and the active agent.This results in a composition which rapidly loses effectiveness as itbegins to dissipate from the site of action. It would therefore be ofconsiderable value to provide topical formulations which werebioadherant, even to mucousal surfaces, and which could be formulated asa low viscosity preformulation which would become adherent upon contactwith the desired surface. Furthermore it would be a significantadvantage if the formulation was protective, non-irritant, and showedreasonable resistance to wear and exposure to aqueous ambient.

The present inventors have now established that by providing apre-formulation comprising certain amphiphilic components, at least onebioactive agent and a biologically tolerable solvent, especially in alow viscosity phase such as molecular solution, the pre-formulation maybe generated addressing many of the shortfalls of previous formulations.In particular, the pre-formulation is easy to manufacture, may besterile-filtered, it has low viscosity (allowing easy and rapidadministration), and/or allows a high level of bioactive agent to beincorporated (thus allowing a smaller amount of composition to be usedand/or providing a long effective lifetime). The compositions are formedfrom materials that are non-toxic, biotolerable and biodegradable. Theyare suited for application at sensitive areas such as sensitive parts ofthe body and sites of inflammation, and comprising lipids which are partof natural protective surface linings, e.g. phospholipids. Furthermore,due to the combination of bioadhesive properties and extremely lowaqueous solubility of main constituents the compositions, the appliedcomposition of the invention are stable to exposure to aqueous media andwear. The composition furthermore provides sustained release of a widerange of actives with a tuneable window of duration. The pre-formulationis therefore highly suitable for the formation of depot compositionsfollowing non-parenteral (e.g. topical) administration to body cavitiesand/or surfaces of the body or elsewhere and are formed from lipidswhich may provide inherent benefits in themselves in addition to forminghighly effective carriers and topical depots for active agents.

In a first aspect, the present invention thus provides a pre-formulationcomprising a low viscosity mixture of:

a) at least one neutral diacyl lipid and/or a tocopherol;b) at least one phospholipid;c) at least one biocompatible, (preferably oxygen containing) organicsolvent;including at least one bioactive agent which is dissolved or dispersedin the low viscosity mixture, wherein the pre-formulation forms, or iscapable of forming, at least one liquid crystalline phase structure uponcontact with an aqueous fluid and/or body surface.

Generally, the aqueous fluid will be a body fluid such as fluid from amucosal surface, tears, sweat, saliva, gastro-intestinal fluid,extra-vascular fluid, extracellular fluid, interstitial fluid or plasma,and the pre-formulation will form a liquid crystalline phase structurewhen contacted with a body surface, area or cavity (e.g. in vivo) uponcontact with the aqueous body fluid. The pre-formulation of theinvention will generally not contain any significant quantity of waterprior to administration.

In a second aspect of the invention, there is also provided a method ofdelivery of a bioactive agent to a human or non-human animal (preferablymammalian) body, this method comprising topically administering apre-formulation comprising a low viscosity mixture of:

a) at least one neutral diacyl lipid and/or a tocopherol;b) at least one phospholipid;c) at least one biocompatible, (preferably oxygen containing) organicsolvent;and including at least one bioactive agent dissolved or dispersed in thelow viscosity mixture; whereby to form at least one liquid crystallinephase structure upon contact with an aqueous fluid at a body surfacefollowing administration. Preferably, the pre-formulation administeredin such a method is a pre-formulation of the invention as describedherein.

The method of administration suitable for the above method of theinvention will be a method appropriate for the condition to be treatedand the bioactive agent used. A bioadhesive non-parenteral (e.g.topical) depot composition may be formed by administration to thesurface of skin, mucous membranes and/or nails, to opthalmological,nasal, oral or internal surfaces or to cavities such as nasal, rectal,vaginal or buccal cavities, the periodontal pocket or cavities formedfollowing extraction of a natural or implanted structure or prior toinsertion of an implant (e.g a joint, stent, cosmetic implant, tooth,tooth filling or other implant).

In a further aspect, the present invention also provides a method forthe preparation of a liquid crystalline composition (especially a depotcomposition) comprising exposing a pre-formulation comprising a lowviscosity mixture of:

a) at least one neutral diacyl lipid and/or a tocopherol;b) at least one phospholipid;c) at least one biocompatible (preferably oxygen containing), organicsolvent;and at least one bioactive agent dissolved or dispersed in the lowviscosity mixture, to an aqueous fluid at a body surface. Preferably thepre-formulation administered is a pre-formulation of the presentinvention as described herein. The exposure to a fluid may be internallywithin at an internal surface of a body cavity, or may be at an externalbody surface such as a skin surface, depending upon the nature of thecomposition and any active agent.

The liquid crystalline composition formed in this method is bioadhesiveas described herein.

In a still further aspect the present invention provides a process forthe formation of a pre-formulation suitable for the administration of abioactive agent to a surface of a (preferably mammalian) subject, saidprocess comprising forming a low viscosity mixture of

a) at least one neutral diacyl lipid and/or a tocopherol;b) at least one phospholipid;c) at least one biocompatible (preferably oxygen containing), organicsolvent;and dissolving or dispersing at least one bioactive agent in the lowviscosity mixture, or in at least one of components a, b or c prior toforming the low viscosity mixture. Preferably the pre-formulationso-formed is a formulation of the invention as described herein.

In a yet still further aspect the present invention provides the use ofa low viscosity mixture of:

a) at least one neutral diacyl lipid and/or a tocopherol;b) at least one phospholipid;c) at least one biocompatible (preferably oxygen containing), organicsolvent;wherein at least one bioactive agent is dissolved or dispersed in thelow viscosity mixture in the manufacture of a pre-formulation for use inthe sustained local administration of said active agent, wherein saidpre-formulation is capable of forming at least one liquid crystallinephase structure upon contact with an aqueous fluid.

In a further aspect, the present invention provides a method for thetreatment of a human or animal subject comprising administration of acomposition of the present invention, including an active agent. In thisaspect, the method of treatment is in particular a method for thetreatment of inflammation and/or irritation, especially at a bodysurface and/or in a body cavity such as the gastrointestinal tract.

In a still further aspect, the present invention provides for the use ofa composition of the present invention in therapy, and in particularlyfor the use of a composition of the present invention, including anactive agent, in the manufacture of a medicament for the treatment ofinflammation and/or irritation, especially at a body surface and/or in abody cavity such as the gastrointestinal tract.

The use of non-lamellar phase structures (such as liquid crystallinephases) in the delivery of bioactive agents is now relatively wellestablished. Such structures form when an amphiphilic compound isexposed to a solvent because the amphiphile has both polar and apolargroups which cluster to form polar and apolar regions. These regions caneffectively solubilise both polar and apolar compounds. In addition,many of the structures formed by amphiphiles in polar and/or apolarsolvents have a very considerable area of polar/apolar boundary at whichother amphiphilic compounds can be adsorbed and stabilised. Amphiphilescan also be formulated to protect active agents, to at least someextent, from aggressive biological environments, including enzymes, andthereby provide advantageous control over active agent stability andrelease.

The formation of non-lamellar regions in the amphiphile/water,amphiphile/oil and amphiphile/oil/water phase diagrams is a well knownphenomenon. Such phases include liquid crystalline phases such as thecubic P, cubic D, cubic G and hexagonal phases, which are fluid at themolecular level but show significant long-range order, and the L3 phasewhich comprises a multiply interconnected bi-continuous network ofbilayer sheets which are non-lamellar but lack the long-range order ofthe liquid crystalline phases. Depending upon their curvature of theamphiphile sheets, these phases may be described as normal (meancurvature towards the apolar region) or reversed (mean curvature towardsthe polar region).

The non-lamellar liquid crystalline and L3 phases are thermodynamicallystable systems. That is to say, they are not simply a meta-stable statethat will separate and/or reform into layers, lamellar phases or thelike, but are the stable thermodynamic form of the lipid/solventmixture.

As used herein, the term “low viscosity mixture” is used to indicate amixture which may be readily administered to a subject and in particularreadily administered by means of a standard syringe and needle orpump/aerosol spray arrangement. This may be indicated, for example bythe ability to be dispensed from a 1 ml disposable syringe through a 22awg (or a 23 gauge) needle by manual pressure. In a particularlypreferred embodiment, the low viscosity mixture should be a mixturecapable of passing through a standard sterile filtration membrane suchas a 0.22 μm syringe filter. In other preferred embodiments, a similarfunctional definition of a suitable viscosity can be defined as theviscosity of a pre-formulation that can be sprayed using a compressionpump or pressurized spray device using conventional spray equipment. Atypical range of suitable viscosities would be, for example, 0.1 to 5000mPas, preferably 1 to 1000 mPas at 20° C.

It has been observed that by the addition of small amounts of lowviscosity solvent, as indicated herein, a very significant change inviscosity can be provided. As indicated in FIG. 2, for example, theaddition of only 5% solvent can reduce viscosity 100-fold and additionof 10% may reduce the viscosity up to 10,000 fold.

In order to achieve this non-linear, synergistic effect, in loweringviscosity it is important that a solvent of appropriately low viscosityand suitable polarity be employed. Such solvents include those describedherein infra.

Particularly preferred examples of low viscosity mixtures are molecularsolutions and/or isotropic phases such as L2 and/or L3 phases. Asdescribe above, the L3 is a non-lamellar phase of interconnected sheetswhich has some phase structure but lacks the long-range order of aliquid crystalline phase. Unlike liquid crystalline phases, which aregenerally highly viscous, L3 phases are of lower viscosity. Obviously,mixtures of L3 phase and molecular solution and/or particles of L3 phasesuspended in a bulk molecular solution of one or more components arealso suitable. The L2 phase is the so-called “reversed micellar” phaseor microemulsion. Most preferred low viscosity mixtures are molecularsolutions, L3 phases and mixtures thereof. L2 phases are less preferred,except in the case of swollen L₂ phases as described below.

The present invention provides a pre-formulation comprising componentsa, b, c and at least one bioactive agent as indicated herein. One of theconsiderable advantages of the pre-formulations of the invention is thatcomponents a and b may be formulated in a wide range of proportions. Inparticular, it is possible to prepare and use pre-formulations of thepresent invention having a much greater proportion of phospholipid toneutral, diacyl lipid and/or tocopherol than was previously achievablewithout risking phase separation and/or unacceptably high viscosities inthe pre-formulation. The weight ratios of components a:b may thus beanything from 5:95 right up to 95:5. Preferred ratios would generally befrom 90:10 to 20:80 and more preferably from 85:15 to 30:70. In onepreferred embodiment of the invention, there is a greater proportion ofcomponent b than component a. That is, the weight ratio a:b is below50:50, e.g. 48:52 to 2:98, preferably, 40:60 to 10:90 and morepreferably 35:65 to 20:80.

In on preferred embodiment, the compositions are bioadhesive and theratio of components a:b is in the range 80:20 to 40:60, preferably 70:30to 50:50. A particularly suitable range is around 65:35 a:b, such asbetween 75:25 and 55:45.

The amount of component c in the pre-formulations of the invention willbe at least sufficient to provide a low viscosity mixture (e.g. amolecular solution, see above) of components a, b and c and will beeasily determined for any particular combination of components bystandard methods. The phase behaviour itself may be analysed bytechniques such as visual observation in combination with polarizedlight microscopy, nuclear magnetic resonance, and cryo-transmissionelectron microscopy (cryo-TEM) to look for solutions, L2 or L3 phases,or liquid crystalline phases. Viscosity may be measured directly bystandard means. As described above, an appropriate practical viscosityis that which can effectively be syringed and particularly sterilefiltered and/or sprayed from a pump or pressurised spray. This will beassessed easily as indicated herein. The maximum amount of component cto be included will depend upon the exact application of thepre-formulation but generally the desired properties will be provided byany amount forming a low viscosity mixture (e.g. a molecular solution,see above) and/or a solution with sufficiently low viscosity.

Since the administration of unnecessarily large amounts of solvent to asubject is generally undesirable the amount of component c may, in oneembodiment, be limited to no more than ten times (e.g. three times) theminimum amount required to form a low viscosity mixture, preferably nomore than five times and most preferably no more than twice this amount.

Higher proportions of solvent may also be used for the non-parenteral(e.g. topical) applications of the invention, however, especially whenapplied to external body surfaces, where the solvent will be lost byevaporation rather than absorbed into the body. For such applications upto 100 times the minimum amount of solvent may be used (e.g. up to 95%by weight of the composition, preferably up to 80% by weight and morepreferably up to 50% by weight), especially where a very thin layer ofthe resulting non-parenteral depot is desired.

Where the compositions of the invention are formulated as aerosol spraycompositions (e.g. for topical or delivery of an active), thecomposition may also comprise a propellant. Such compositions may alsoinclude a high proportion of solvent component c), as considered above,since much of the solvent will evaporate when the composition isdispensed, particularly under the influence of the propellant.

Suitable propellants are volatile compounds which will mix with thecomposition of the invention under the pressure of the spray dispenser,without generating high viscosity mixtures. They should evidently haveacceptable biocompatibility. Suitable propellants will readily beidentified by simple testing and examples include hydrocarbons(especially C₁ to C₄ hydrocarbons), carbon dioxide and nitrogen.Volatile hydrofluorocarbons such as HFCs 134, 134a, 227ea and/or 152amay also be suitable.

As a general guide, the weight of component c will typically be around0.5 to 50% of the total weight of the a-b-c solution. This proportionmay be limited to 2 to 30% or 5 to 20% by weight. As indicated above;however, in case of a spray composition, especially with a propellant,the amount of c may exceed 50%.

The formulations of the invention may additionally contain smallproportions of other agent, such as polymers which are soluble in theprecursor. Such polymers may act as a reinforcement of the swollenliquid crystalline phase so that a film attached to a mucosal surface ismore strongly attached. A “reinforcement” along the same principle couldalso be obtained by soaking a matrix (paper, polymer net, or similar)with the precursor. Upon applying this “patch” to the skin theformulation may by itself act as the glue. In contrast to conventionaladhesives for coating damaged tissue, whoever, the formulations of theinvention are adhesive even to mucous membranes and are not irritant. Inmany cases, they are in fact soothing in themselves, as describedherein, and may contain suitable active agent.

Component “a” as indicated herein is a neutral lipid componentcomprising a polar “head” group and also non-polar “tail” groups.Generally the head and tail portions of the lipid will be joined by anester moiety but this attachment may be by means of an ether, an amide,a carbon-carbon bond or other attachment. Preferred polar head groupsare non-ionic and include polyols such as glycerol, diglycerol and sugarmoieties (such as inositol and glucosyl based moieties); and esters ofpolyols, such as acetate or succinate esters. Preferred polar groups areglycerol and diglycerol, especially glycerol.

In one preferred aspect, component a is a diacyl lipid in that it hastwo non-polar “tail” groups. This is generally preferable to the use ofmono-acyl (“lyso”) lipids because these are typically less welltolerated in vivo. The two non-polar groups may have the same or adiffering number of carbon atoms and may each independently be saturatedor unsaturated. Examples of non-polar groups include C₆-C₃₂ alkyl andalkenyl groups, which are typically present as the esters of long chaincarboxylic acids. These are often described by reference to the numberof carbon atoms and the number of unsaturations in the carbon chain.Thus, CX:Z indicates a hydrocarbon chain having X carbon atoms and Zunsaturations. Examples particularly include caproyl (C6:0), capryloyl(C8:0), capryl (C10:0), lauroyl (C12:0), myristoyl (C14:0), palmitoyl(C16:0), phytanoly (C16:0), palmitoleoyl (C16:1), stearoyl (C18:0),oleoyl (C18:1), elaidoyl (C18:1), linoleoyl (C18:2), linolenoyl (C18:3),arachidonoyl (C20:4), behenoyl (C22:0) and lignoceroyl (C24:9) groups.Thus, typical non-polar chains are based on the fatty acids of naturalester lipids, including caproic, caprylic, capric, lauric, myristic,palmitic, phytanic, palmitolic, stearic, oleic, elaidic, linoleic,linolenic, arachidonic, behenic or lignoceric acids, or thecorresponding alcohols. Preferable non-polar chains are palmitic,stearic, oleic and linoleic acids, particularly oleic acid.

The diacyl lipid, when used as all or part of component “a”, may besynthetic or may be derived from a purified and/or chemically modifiednatural sources such as vegetable oils. Mixtures of any number of diacyllipids may be used as component a. Most preferably this component willinclude at least a portion of diacyl glycerol (DAG), especially glyceroldioleate (GDO). In one favoured embodiment, component a consists ofDAGs. These may be a single DAG or a mixture of DAGs. A highly preferredexample is DAG comprising at least 50%, preferably at least 80% and evencomprising substantially 100% GDO.

An alternative or additional highly preferred class of compounds for useas all or part of component a are tocopherols. As used herein, the term“a tocopherol” is used to indicate the non-ionic lipid tocopherol, oftenknown as vitamin E, and/or any suitable salts and/or analogues thereof.Suitable analogues will be those providing the phase-behaviour, lack oftoxicity, and phase change upon exposure to aqueous fluids, whichcharacterise the compositions of the present invention. Such analogueswill generally not form liquid crystalline phase structures as a purecompound in water. The most preferred of the tocopherols is tocopherolitself, having the structure below. Evidently, particularly where thisis purified from a natural source, there may be a small proportion ofnon-tocopherol “contaminant” but this will not be sufficient to alterthe advantageous phase-behaviour or lack of toxicity. Typically, atocopherol will contain no more than 10% of non-tocopherol-analoguecompounds, preferably no more than 5% and most preferably no more than2% by weight.

In a further advantageous embodiment of the invention, component a)consists essentially of tocopherols, in particular tocopherol as shownabove.

A preferred combination of constituents for component a) is a mixture ofat least one DAG (e.g. GDO) with at least one tocopherol. Such mixturesinclude 2:98 to 98:2 by weight tocopherol:GDO, e.g. 10:90 to 90:10tocopherol:GDO and especially 20:80 to 80:20 of these compounds. Similarmixtures of tocopherol with other DAGs are also suitable.

Component “b” in the present invention is at least one phospholipid. Aswith component a, this component comprises a polar head group and atleast one non-polar tail group. The difference between components a andb lies principally in the polar group. The non-polar portions may thussuitably be derived from the fatty acids or corresponding alcoholsconsidered above for component a. It will typically be the case that thephospholipid will contain two non-polar groups, although one or moreconstituents of this component may have one non-polar moiety. Where morethan one non-polar group is present these may be the same or different.

Preferred phospholipid polar “head” groups include phosphatidylcholine,phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol.Most preferred is phosphatidylcholine (PC). In a preferred embodiment,component b) thus consists of at least 50% PC, preferably at least 70%PC and most preferably at least 80% PC. Component b) may consistessentially of PC.

The phospholipid portion, even more suitably than any diacyl lipidportion, may be derived from a natural source. Suitable sources ofphospholipids include egg, heart (e.g. bovine), brain, liver (e.g.bovine) and plant sources including soybean. Such sources may provideone or more constituents of component b, which may comprise any mixtureof phospholipids.

Since the pre-formulations of the invention may be administered to asubject for the controlled release of an active agent, it is preferablethat the components a and b are biocompatible. In this regard, it ispreferable to use, for example, diacyl lipids and phospholipids ratherthan mono-acyl (lyso) compounds. A notable exception to this istocopherol, as described above. Although having only one alkyl chain,this is not a “lyso” lipid in the convention sense. The nature oftocopherol as a well tolerated essential vitamin evidently makes ithighly suitable in biocompatibility.

The nature of the compositions of the invention as being suitable forsoothing and healing irritation and inflammation at a body surface makesthe need to well tolerated lipids highly important. In particular, thelipid composition will be present at high concentration in contact withtissue which may be damaged or inflamed. As a result, the very highlevel of compatibility of, for example, the diacyl lipids of the presentinvention, is significant in comparison with less well toleratedcomponents such as mono-acyl lipids.

It is furthermore most preferable that the lipids and phospholipids ofcomponents a and b are naturally occurring (whether they are derivedfrom a natural source or are of synthetic origin). Naturally occurringlipids tend to cause lesser amounts of inflammation and reaction fromthe body of the subject. Not only is this more comfortable for thesubject but it may increase the residence time of the resulting depotcomposition, since less immune system activity is recruited to theadministration site and there is less tendency for the subject todisturb the area. In certain cases it may, however, be desirable toinclude a portion of a non-naturally-occurring lipid in components aand/or b. This might be, for example an “ether lipid” in which the headand tail groups are joined by an ether bond rather than an ester. Suchnon-naturally-occurring lipids may be used, for example, to alter therate of degradation of the resulting depot-composition by having agreater or lesser solubility or vulnerability to breakdown mechanismspresent at the site of active agent release. Although all proportionsfall within the scope of the present invention, generally, at least 50%of each of components a and b will be naturally occurring lipids. Thiswill preferably be at least 75% and may be up to substantially 100%.

Two particularly preferred combinations of components a and b are GDOwith PC and tocopherol with PC, especially in the region 30-90 wt %GDO/tocopherol, 10-60 wt % PC and 1-30% solvent (especially ethanol, NMPand/or isopropanol). Most preferred combinations are 35-60% (e.g. 40-55)GDO with 20 to 50% (e.g. 25 to 45%) PC. These are especially suitable incombination with ethanol, particularly at 5 to 25% (e.g. 7 to 19%).

In addition to amphiphilic components a and b, the pre-formulations ofthe invention may also contain additional amphiphilic components atrelatively low levels. In one embodiment of the invention, thepre-formulation contains up to 10% (by weight of components a and b) ofa charged amphiphile, particularly an anionic amphiphile such as a fattyacid. Preferred fatty acids for this purpose include caproic, caprylic,capric, lauric, myristic, palmitic, phytanic, palmitolic, stearic,oleic, elaidic, linoleic, linolenic, arachidonic, behenic or lignocericacids, or the corresponding alcohols.

Preferable fatty acids are palmitic, stearic, oleic and linoleic acids,particularly oleic acid. It is particularly advantageous that thiscomponent be used in combination with a cationic peptide active agent(see below). The combination of an anionic lipid and a cationic peptideis believed to provide a sustained release composition of particularvalue. This may in part be due to increased protection of the peptidefrom the degradative enzymes present in vivo.

Component “c” of the pre-formulations of the invention is an oxygencontaining organic solvent. Since the pre-formulation is to generate adepot/bioadhesive composition following administration (e.g. in vivo),upon contact with an aqueous fluid, it is desirable that this solvent betolerable to the subject and be capable of mixing with the aqueousfluid, and/or diffusing or dissolving out of the pre-formulation intothe aqueous fluid. Solvents having at least moderate water solubilityare thus preferred.

A special case is where the composition of the invention is formulatedas aerosol spray compositions. Here component c may be seen to comprisethe propellant, having a low aqueous solubility. All mixing ratios fromessentially pure propellant to mainly oxygen containing organic solventsmay be considered. When dispensing the formulation the propellant willto a large degree evaporate. When c mainly constitutes propellant aninstant increase of viscosity may be observed after spraying theformulation. This is due to rapid evaporation of the propellant and mayhave the advantage of a more effective initial retention at theapplication site, and the potential disadvantage that the formulationhas a low viscosity during “curing” (uptake of water and phasetransformation to a liquid crystalline phase with high viscosity) iscircumvented.

In a preferred version, the solvent is such that a relatively smalladdition to the composition comprising a and b, i.e. below 20%, or morepreferably below 16%, e.g. up to 10% or even below give a largeviscosity reductions of one order of magnitude or more. As describedherein, the addition of 10% solvent can give a reduction of two, threeor even four orders of magnitude in viscosity over the solvent-freecomposition, even if that composition is a solution or L₂ phasecontaining no solvent, or an unsuitable solvent such as water (subjectto the special case considered below), or glycerol.

Typical solvents suitable for use as component c include at least onesolvent selected from alcohols, ketones, esters (including lactones),ethers, amides and sulphoxides. Examples of suitable alcohols includeethanol, isopropanol and glycerol formal. Monools are preferred to diolsand polyols. Where diols or polyols are used, this is preferably incombination with an at least equal amount of monool or other preferredsolvent. Examples of ketones include acetone, n-methyl pyrrolidone(NMP), 2-pyrrolidone, and propylene carbonate. Suitable ethers includediethylether, glycofurol, diethylene glycol monoethyl ether,dimethylisobarbide, and polyethylene glycols. Suitable esters includeethyl acetate and isopropyl acetate and dimethyl sulphide is as suitablesulphide solvent. Suitable amides and sulphoxides includedimethylacetamide (DMA) and dimethylsulphoxide (DMSO), respectively.Less preferred solvents include dimethyl isosorbide, tetrahydrofurfurylalcohol, diglyme and ethyl lactate. The most preferred solvent comprisesethanol and in particular consists of at least 80% ethanol, preferablyat least 90% ethanol.

Since the pre-formulations are to be administered to a living subject,it is necessary that the solvent component c is sufficientlybiocompatible. The degree of this biocompatibility will depend upon theapplication method and since component c may be any mixture of solvents,a certain amount of a solvent that would not be acceptable in largequantities may evidently be present. Overall, however, the solvent ormixture forming component c must not provoke unacceptable reactions fromthe subject upon administration. Generally such solvents will behydrocarbons or preferably oxygen containing hydrocarbons, bothoptionally with other substituents such as nitrogen containing groups.It is preferable that little or none of component c contains halogensubstituted hydrocarbons since these tend to have lowerbiocompatibility. Where a portion of halogenated solvent such asdichloromethane or chloroform is necessary, this proportion willgenerally be minimised. Evidently, the range of suitable solvents willbe greater in formulations for application to sound, external surfacesthan to internal, sensitive and/or damaged surfaces, where only the mostbiocompatible will typically be acceptable. In addition, in the case ofaerosol spray compositions also halogenated hydrocarbons may beconsidered as propellant, since it will evaporate to a large degreeduring dispensing.

Component c as used herein may be a single solvent or a mixture ofsuitable solvents but will generally be of low viscosity. This isimportant because one of the key aspects of the present invention isthat it provides preformulations that are of low viscosity and a primaryrole of a suitable solvent is to reduce this viscosity. This reductionwill be a combination of the effect of the lower viscosity of thesolvent and the effect of the molecular interactions between solvent andlipid composition. One observation of the present inventors is that theoxygen-containing solvents of low viscosity described herein have highlyadvantageous and unexpected molecular interactions with the lipid partsof the composition, thereby providing a non-linear reduction inviscosity with the addition of a small volume of solvent.

The viscosity of the “low viscosity” solvent component c (single solventor mixture) should typically be no more than 18 mPas at 20° C. This ispreferably no more than 15 mPas, more preferably no more than 10 mPasand most preferably no more than 7 mPas at 20° C.

The solvent component c will generally be at least partially lost uponformation of the depot/bioadhesive composition on contact with a surface(e.g. a body surface or the surface of an implant), or diluted byabsorption of water from the surrounding air and/or tissue. It ispreferable, therefore, that component c be at least to some extent watermiscible and/or dispersible and at least should not repel water to theextent that water absorption is prevented. In this respect also, oxygencontaining solvents with relatively small numbers of carbon atoms (forexample up to 10 carbons, preferably up to 8 carbons) are preferred.Obviously, where more oxygens are present a solvent will tend to remainsoluble in water with a larger number of carbon atoms. The carbon toheteroatom (e.g. N, O, preferably oxygen) ratio will thus often bearound 1:1 to 6:1, preferably 2:1 to 4:1. Where a solvent with a ratiooutside one of these preferred ranges is used then this will preferablybe no more than 75%, preferably no more than 50%, in combination with apreferred solvent (such as ethanol). This may be used, for example todecrease the rate of evaporation of the solvent from the pre-formulationin order to control the rate of liquid crystalline depot formation.

A further advantage of the present pre-formulations is that a higherlevel of bioactive agent may be incorporated into the system. Inparticular, by appropriate choice of components a-c (especially c), highlevels of active agent may be dissolved or suspended in thepre-formulations. Generally, the lipid components in the absence ofwater are relatively poorly solubilising but in the presence of waterform phases too viscous to administer easily. Higher proportions ofbioactive agent may be included by use of appropriate solvents ascomponent c and this level will either dissolve in the depot compositionas it forms in situ or may form microdrops or microcrystals which willgradually dissolve and release active agent. A suitable choice ofsolvent will be possible by routine experimentation within theguidelines presented herein. In particular, the present inventors haveestablished that the combination of a low molecular weight alcoholsolvent (such as ethanol or isopropanol) with the lipid components ofthe present invention is unexpectedly effective in solubilising a widerange of drugs and other active molecules.

The pre-formulations of the present invention typically do not containsignificant amounts of water. Since it is essentially impossible toremove every trace of water from a lipid composition, this is to betaken as indicating that only such minimal trace of water exists ascannot readily be removed. Such an amount will generally be less than 1%by weight, preferably less that 0.5% by the weight of thepre-formulation. In one preferred aspect, the pre-formulations of theinvention do not contain glycerol, ethylene glycol or propylene glycoland contain no more than a trace of water, as just described.

In some cases the composition may contain a trace of water (or a polarsolvent with similar properties) such that it forms a rather low viscousL2 (reversed micellar) phase. This can also help to solubilise certainactives in the formulation, particularly those which are only soluble inwater.

There is, however, a certain embodiment of the present invention inwhich higher proportions of water may be tolerated. This is where wateris present as a part of the solvent component in combination with anadditional water-miscible component c (single solvent or mixture). Inthis embodiment, up to 10 wt % water may be present providing that atleast 3 wt %, preferably at least 5% and more preferably at least 7 wt %component c is also present, that component c is water miscible, andthat the resulting preformulation remains non-viscous and thus does notform a liquid crystalline phase. Generally there will be a greateramount of component c) by weight than the weight of water included inthe preformulation. Most suitable solvents of use with water in thisaspect of the invention include ethanol, isopropyl alcohol, NMP, acetoneand ethyl acetate.

The pre-formulations of the present invention contain one or morebioactive agents (described equivalently as “active agents” herein).Active agents may be any compound having a desired biological orphysiological effect, such as a protein, drug, antigen, nutrient,cosmetic, fragrance, flavouring, diagnostic, pharmaceutical, vitamin, ordietary agent and will be formulated at a level sufficient to provide anin vivo concentration at a functional level (this generally being alocal concentration for topical compositions).

Drug agents that may be delivered by the present invention include drugswhich act on cells and receptors, such as peripheral nerves, adrenergicreceptors, and cholinergic receptors, the skeletal muscles, thecardiovascular system, smooth muscles, the blood circulation system,endocrine and hormone system, blood circulatory system, synoptic sites,neuroeffector junctional sites, the immunological system, thereproductive system, the skeletal system, autacoid system, thealimentary and excretory systems, the histamine system, and the centralnervous system. Drug agents intended for local stimulatory or inhibitoryeffects on enzymes or proteins can also be delivered by the presentinvention. The effect of the delivered drug agent may also be associatedwith direct effects on DNA and/or RNA synthesis, such as ontranscription, translation, or post-translational modification. Alsothese effects may be both stimulatory and inhibitory.

Examples of drugs which may be delivered by the composition of thepresent invention include, but are not limited to, antibacterial agentssuch as β-lactams or macrocyclic peptide antibiotics, anti fungal agentssuch as polyene macrolides (e.g. amphotericin B) or azole antifungals,anticancer and/or anti viral drugs such as nucleoside analogues,paclitaxel and derivatives thereof, anti inflammatorys, such asnon-steroidal anti inflammatory drugs and corticosteroids,cardiovascular drugs such as blood-pressure lowing or raising agents(especially locally acting), analgesics, and prostaglandins andderivatives. Preferably the drug delivered is a corticosteroid, morepreferably a Group A, Group B and/or Group C corticosteroid, with GroupA corticosteroids being a preferred example. Diagnostic agents includeradionuclide labelled compounds and contrast agents including X-ray,ultrasound and MRI contrast enhancing agents (especially for applicationto an internal surface of a body cavity). Nutrients include vitamins,coenzymes, dietary supplements etc which may, for example, be used forlocal rescue from the effects of a systemic drug, such as rescue byfolate from a folate analogue such as methotrexate.

Particularly suitable active agents include those which would normallyhave a short residence time in the body due to rapid breakdown orexcretion and those with poor oral bioavailability, especially wheretheir effect may be provided by topical treatment, thereby bypassingsystemic absorption. These include peptide, protein and nucleic acidbased active agents, hormones and other naturally occurring agents intheir native or modified forms. By administering such agents in the formof a bioadhesive depot composition formed from the pre-formulation ofthe present invention, the agents are provided at a sustained level foran extended length of time in spite of having rapid systemic clearancerates. This offers obvious advantages in terms of stability and patientcompliance over dosing multiple times each day for the same period. Inone preferred embodiment, the active agent thus has a biological halflife (upon entry into the blood stream) of less than 1 day, preferablyless than 12 hours and more preferably less than 6 hours. In some casesthis may be as low as 1-3 hours or less. Suitable agents are also thosewith poor oral bioavailability relative to that achieved by injection,for where the active agent also or alternatively has a bioavailabilityof below 0.1%, especially below 0.05% in oral formulations. Similarly,certain agents would be unsuitable or undesirable when administeredsytemically but may be administered locally, particularly to externalsurfaces.

Peptide and protein based active agents are highly suitable forinclusion in the surface-applied depot compositions of the invention.Such agents may be included for their local effect, or may be applied ata surface for systemic action. Suitable actives for local or systemiceffect include human and veterinary drugs selected from the groupconsisting of adrenocorticotropic hormone (ACTH) and its fragments,angiotensin and its related peptides, antibodies and their fragments,antigens and their fragments, atrial natriuretic peptides, bioadhesivepeptides, Bradykinins and their related peptides, calcitonins and theirrelated peptides, cell surface receptor protein fragments, chemotacticpeptides, cyclosporins, cytokines, Dynorphins and their relatedpeptides, endorphins and P-lidotropin fragments, enkephalin and theirrelated proteins, enzyme inhibitors, immunostimulating peptides andpolyaminoacids, fibronectin fragments and their related peptides,gastrointestinal peptides, gonadotrophin-releasing hormone (GnRH)agonists and antagonist, glucagons like peptides, growth hormonereleasing peptides, immunostimulating peptides, insulins andinsulin-like growth factors, interleukins, luthenizing hormone releasinghormones (LHRH) and their related peptides, melanocyte stimulatinghormones and their related peptides, nuclear localization signal relatedpeptides, neurotensins and their related peptides, neurotransmitterpeptides, opioid peptides, oxytocins, vasopressins and their relatedpeptides, parathyroid hormone and its fragments, protein kinases andtheir related peptides, somatostatins and their related peptides,substance P and its related peptides, transforming growth factors (TGF)and their related peptides, tumor necrosis factor fragments, toxins andtoxoids and functional peptides such as anticancer peptides includingangiostatins, antihypertension peptides, anti-blood clotting peptides,and antimicrobial peptides; selected from the group consisting ofproteins such as immunoglobulins, angiogenins, bone morphogenicproteins, chemokines, colony stimulating factors (CSF), cytokines,growth factors, interferons (Type I and II), interleukins, leptins,leukaemia inhibitory factors, stem cell factors, transforming growthfactors and tumor necrosis factors.

In a preferred embodiment, applicable to all aspects of the invention,the active agent is at least one corticosteroid. For example at leastone hydrocortisone type (Group A), acetonide type (Group B),betamethasone type (Group C), or ester type (Group D) corticosteroid.Preferably the active agent is at least one group A and/or at least onegroup B and/or at least one group C corticosteroid, such as at least onefrom the group consisting of hydrocortisone, hydrocortisone acetate,cortisone acteate, tixocortol pivalate, prednisolone,methylprednisolone, prednisone, triamcinolone acetonide, triamcinolonealcohol, mometason, amcinonide, budesonide, desonide, fluocinonide,fluocinonide acetonide, halcinonide, betamethasone, betamethasone sodiumphosphate, dexamethasone, dexamethasone sodium phosphate, andfluocortolone. Most preferably the active agent is tramcinolone or asalt thereof, such as triamcinolone acetonide or triamcinolone alcohol.

A further considerable advantage of the depot compositions of thepresent invention is that active agents are released gradually over longperiods without the need for repeated dosing. The composition are thushighly suitable for children or people who's lifestyle is incompatiblewith a reliable or repeated dosing regime. Also for “lifestyle” activeswhere the inconvenience of repeated dosing might outweigh the benefit ofthe active.

Cationic peptides are particularly suitable for use where a portion ofthe pre-formulation comprises an anionic amphiphile such as a fattyacid. In this embodiment, preferred peptides include octreotide,lanreotide, calcitonin, oxytocin, interferon-beta and -gamma,interleukins 4, 5, 7 and 8 and other peptides having an isoelectricpoint above pH 7, especially above pH 8.

In one preferred aspect of the present invention, the composition of theinvention is such that an I₂ phase, or a mixed phase including I₂ phaseis formed upon exposure to aqueous fluids and a polar active agent isincluded in the composition. Particularly suitable polar active agentsinclude peptide and protein actives, oligo nucleotides, and small watersoluble actives, including those listed above. Of particular interest inthis aspect are the peptide octreotide and other somatostatin relatedpeptides, interferons alpha and beta, glucagon-like peptides 1 and 2 andtheir receptor agonists, luprorelin and other GnRH agonist, abarelix andother GnRH antagonists, interferon alpha and beta, zolendronate andibandronate and other bisphosponates, and polar active chlorhexidine(e.g. chlorhexidine digluconate or chlorhexidine dihydrochloride).

The amount of bioactive agent to be formulated with the pre-formulationsof the present invention will depend upon the functional dose and theperiod during which the depot composition formed upon administration isto provide sustained release. Typically, the dose formulated for aparticular agent will be around the equivalent of the normal single dosemultiplied by the number times greater the expected duration of actionthe formulation is to provide. Evidently this amount will need to betailored to take into account any adverse effects of a large dose at thebeginning of treatment and so this will generally be the maximum doseused. The precise amount suitable in any case will readily be determinedby suitable experimentation.

The formulations of the present invention may form non-parenteral depotswhere the active agent is slowly released at a body surface. It isparticularly significant that the compositions generated from thepreformulations are bioadhesive because this allows local release of theactive agent over a sustained period. That is to say that thecompositions should coat the surface to which they are applied and/orupon which they form as appropriate and should remain even when thissurface is subject to a flow of air or liquid and/or rubbing. It isparticularly preferable that the liquid crystalline depot compositionsformed should be stable to rinsing with water. For example, a smallvolume (e.g. 100 μl) of depot precursor may be applied to a body surfaceand be exposed to a flow of five hundred times its own volume of waterper minute for 5 minutes. After this treatment, the composition can beconsidered bioadhesive if less than 50% of the composition or bioactiveagent has been lost. Preferably this level of loss will be matched whenwater equaling 1000 times and more preferably 10 000 times the volume ofthe composition is flowed past per minute for five, or preferably 10,minutes.

Another advantageous property of the compositions of the invention isthat the film generated following administration may not only act as adepot system. This film may also have the advantage of loweringevaporation of water from damaged areas or areas afflicted by a medicalcondition (where barrier properties of the skin is reduced). Thus, thecompositions may have further advantageous properties in themselves andshow additive and/or synergistic advantages in combination with activeagents, for instance for the prophylaxis of inflammatory or allergicdermatoses and for the care and restoration of sensitive or stressedskin.

Although the non-parenteral depot compositions of the present inventionmay absorb some or all of the water needed to form a liquid crystallinephase structure from the biological surfaces with which they arecontacted, some additional water may also be absorbed from thesurrounding air. In particular, where a thin layer of high surface areais formed then the affinity of the composition for water may besufficient for it to form a liquid crystalline phase structure bycontact with the water in the air. The “aqueous fluid” referred toherein is thus, at least partially, air containing some moisture in thisembodiment.

Non-parenteral depot compositions will typically be generated byapplying the pre-formulation topically to a body surface (external orwithin a natural or artificially generated body cavity) and/or to thesurface of an implant. This application may be by direct application ofliquid such as by spraying, dipping, rinsing, application from a pad orball roller, intra-cavity injection (e.g to an open cavity with orwithout the use of a needle), painting, dropping (especially into theeyes), applying in the form of a patch, and similar methods. A highlyeffective method is aerosol or pump spraying and evidently this requiresthat the viscosity of the pre-formulation be as low as possible and isthus highly suited to the compositions of the invention. Non-parenteraldepots may, however, be used to administer systemic agents e.g.transmucosally or transdermally.

Where the formulation is administered in the form of a patch, this mayrely on the “glue” function of the composition. This “glue property” maybe beneficial for the tissue contacted by the formulation as thecompositions can be soothing and rehydrating, as indicted herein. Thisis in contrast to previously known patches, where the adhesive istypically inert at best.

Conditions particularly suitable for causative or symptomatic treatmentby topical bioadhesive depot compositions of the present inventioninclude skin conditions (such as soreness resulting from any causeincluding chapping, scratching and skin conditions including eczema andherpes) eye conditions, genital soreness (including that due to genitalinfection such as genital herpes), infections and conditions for thefinger and/or toe nails (such as bacterial or fungal infections of thenails such as onychomycosis or poronychia) and in particularinflammation and/or irritation at any body surface. Two particularlysuitable conditions which may be improved by use of the compositions ofthe invention are oral mucositis and inflammatory bowel disease (e.g.crohn's disease or ulcerative collitus). Topical-type bioadhesiveformulations may also be used to administer systemic active agents (e.g.medication), particularly by skin adsorption, oral, transdermal orrectal routes. Travel sickness medication is a preferred example, as isnicotine (e.g. in anti-smoking aids). Where context permits, “topicalapplication” as referred to herein includes systemic agents appliednon-parenterally to a specific region of the body.

Periodontal infections are particularly suitable for treatment by thecompositions of the present invention. In particular, known compositionsfor treating periodontal infection are difficult to apply or aregenerally ineffective. The most widely used periodontal depotcomposition comprises insertion of a collagen “chip” into theperiodontal space, from which an anti-infective agent is released. Thischip is difficult to insert and does not form to match the shape andvolume of the periodontal space, so that pockets of infection may remainuntreated. In contrast to this, the compositions of the presentinvention, applied as a low viscosity preformulation, can be easily andquickly injected into the periodontal space and will flow to conformexactly to that space and fill the available volume. The compositionsthen quickly absorb water to form a robust gel which is resistant toaqueous conditions of the mouth. The only known previous attempt at suchan injectable periodontal treatment relied on dispersions of relativelyhigh viscosity which were difficult to apply and were subject toundesirable phase separation. All of these drawbacks are now addressedin the compositions of the present invention as described herein. Highlysuitable actives for periodontal administration are anti-antibacterial,antibiotic, anti-inflammatory, and local analgesic agents, in particularbenzydamine, triamcinolone, tramadol and particularly chlorhexidine.

Non-parenteral depot compositions are also of significant benefit incombination with non-pharmaceutical active agents, such as cosmeticactives, fragrances, essential oils etc. Such non-pharmaceutical depotswill maintain the important aspects of bioadhesion and sustained releaseto provide prolonged cosmetic effects, but may easily be applied byspraying or wiping. This additionally applies to agents which have bothcosmetic and medical (especially prophylactic) benefits such assun-protective agents. Since the topical depot compositions providerobust, water resistant barriers which can solubilise high levels ofactives, they are especially suitable for sunscreens and sunblocks incombination with ultra violet light (UV, e.g. UVa, UVb and/or UVc)absorbing and/or scattering agents, particularly where high levels ofprotection is desirable. The compositions are furthermore highlybiocompatible and may act to moisten and soothe the skin during sunexposure. Compositions of the invention containing soothing agents suchas aloe vera are also highly suitable for soothing and moisteningapplication after exposure to sunlight, or to skin which is dry,inflamed or damaged due to, for example irritation, burning or abrasion.

Active agents particularly suited to non-parenteral (e.g. topical) depotadministration, which includes intra oral, buccal, nasal, ophthalmic,dermal, rectal and vaginal delivery routes, include antibacterials suchas chlorhexidine, chloramphenicol, triclosan, tetracycline, terbinafine,tobramycin, fusidate sodium, butenafine, metronidazole (the latterparticularly for the (e.g. symtomatic) treatment of acne rosacea—adultacne or some vaginal infections), antiviral, including acyclovir, antiinfectives such as bibrocathol, ciprofloxacin, levofloxacin, localanalgesics such as benzydamine, lidocaine, prilocaine, xylocaine,bupivacaine, analgesics such as tramadol, fentanyl, sufentanyl,morphine, hydromorphone, methadone, oxycodone, codeine, asperine,acetaminophen, NSAIDS such as ibuprofen, flurbiprofen, naproxene,ketoprofen, fenoprofen, diclofenac, etodalac, diflunisal, oxaproxin,piroxicam, piroxicam, indomethansine, sulindac, tolmethin, salysylicacids such as salisylamide and diflunisal, Cox1 or Cox2 inhibitors suchas celecoxib, rofecoxib or valdecoxib, corticosteroids such as group A,group B and/or group C corticosteroids (for example at least one fromthe group consisting of hydrocortisone, hydrocortisone acetate,cortisone acteate, tixocortol pivalate, prednisolone,methylprednisolone, prednisone, triamcinolone acetonide, triamcinolonealcohol, mometason, amcinonide, budesonide, desonide, fluocinonide,fluocinonide acetonide, halcinonide, betamethasone, betamethasone sodiumphosphate, dexamethasone, dexamethasone sodium phosphate, andfluocortolone), anticancer and immuno stimulating agents (for instance,metylaminolevulinat hydrocloride, interferon alpha and beta),anticonvulsants (for instance tiagabine topiramate or gabapentin),hormones (such as testosterone, and testosterone undecanoate,medroxyprogesterone, estradiol) growth hormones (like human growthhormone), and growth factors (like granulocyte macrophagecolony-stimulating factor), immuno suppressants (cyclosporine,sirolimus, tacrolimus), nicotine and antivirals (e.g. acyclovir),vitamin D3 and derivatives thereof.

Other particularly suitable actives include:

Acetaminophen, Ibuprofen, Propoxyphene, Codeine, Dihydrocodein,Hydrocodone, Oxycodone, Nalbuphine, Meperidine, Leverorphanol,Hydromorphone, Oxymorphone, Alfentanil, Fentanyl and Sefentanil.

Some specific actives found by the inventors to form highly effectivedepots of the present invention include the following:

For topical bioadhesive, controlled release products for intraoral(including buccal & periodontal) administration;

-   i. benzydamine (local analgesic, anti inflammatory) or other local    analgesic, analgesic, anti inflammatory, anti bacterial, anti fungal    or combination thereof. Composition provides sustained effect at    intraoral mucosa, in particular damaged, sensitised, infected mucosa    e.g. in patients suffering from oral mucositis (induced by e.g.    chemo- and radiotherapy). In particular for treatment of oral    mucositis.-   ii. tramadol (analgesic). Provides a composition with sustained    systemic analgesic effect.-   iii. chlorhexidine gluconate (antibacterial) for treatment of    periodontal and topical infections. Particularly for long acting    effect in periodontal pocket. Compositions result in depots    releasing chlorhexidine over more than 1 h, preferably more than 6    h, most preferably more than 24 h when applied as a liquid, forming    a bioadhesive gel in situ. Surface gel formation time observed to be    between 1 second and 5 min.

Depots i to iii formable having high level of active agent incorporationand high degree of resistance to washing away. Preformulations in theform of a liquid administered as spray or liquid wash/rinse for i and iiand gel-forming liquid for iii, wherein liquid is applied to periodontalpocket, e.g. by injection.

For non-parenteral (e.g. topical or systemic) bioadhesive, controlledrelease products for nasal administration;

-   i. fentanyl (analgesic) provides rapid onset and sustained duration    analgesia when administered as spray to the nasal or oral cavity-   ii. diazepam (anti anxiety) provides non-parenteral, nasal or oral    cavity depot with systemic effect giving rapid onset and sustained    duration. Administered as a spray

For topical bioadhesive, controlled release products for ophthalmicadministration;

-   i. diclofenac (NSAID) with sustained duration. Administered as in    situ phase forming liquid-   ii. pilocarpine (parasymptomimetic, cholinergic agonist) for    treatment of glaucoma.-   iii levocabastine hydrochloride, ketotifen fumarate providing liquid    for eye-dropping to give long lasting relief from allergic    conjunctivitis with long period between reapplication.-   iv Pilocarpine hydrochloride for the treatment of Sjögrens syndrome.-   v dexamethasone, (corticosteroid)-   vi chloramphenicol (primarily bacteriostatic antiinfective)-   vii indomethacin (NSAID)

Depots i to vii formulated as liquid spray or more preferably drops fordirect application to eye surface and provide in situ depot formationwith high resistance to washing out by tears and wear from blinking/eyerubbing. Composition of the invention show excellent compatibilityophthalmic application. Safety studies in rabbit models show noirritation and no blurring effects.

Other actives suitable for ophthalmic compositions includeAntihistamines, Mast cell stabilizers, Nonsteroidal anti-inflammatorydrugs (NSAIDs), Corticosteroids (e.g. to treat allergic conjunctivitis)such as group A, group B and/or group C corticosteroids (for example atleast one from the group consisting of hydrocortisone, hydrocortisoneacetate, cortisone acteate, tixocortol pivalate, prednisolone,methylprednisolone, prednisone, triamcinolone acetonide, triamcinolonealcohol, mometason, amcinonide, budesonide, desonide, fluocinonide,fluocinonide acetonide, halcinonide, betamethasone, betamethasone sodiumphosphate, dexamethasone, dexamethasone sodium phosphate, andfluocortolone.), Anti-Glaucoma actives including inflowsuppressing/inhibiting agents (beta blocking agents: timolol, betaxolol,carteolol, levobunolol, etc., topical carbonic anhydrase inhibitors:dorzolamide, brinzolamide, sympathomimetics: epinephrine, dipivefrin,clonidine, apraclonidine, brimonidine), outflow facilitating agents(parasympathomimetics (cholinergic agonists): pilocarpine prostaglandinanalogues and related compounds: atanoprost, travoprost, bimatoprost,unoprostone)

For non-parenteral (e.g. topical or systemic) bioadhesive, controlledrelease products for dermatological administration;

-   i. acyclovir (antiviral). Composition generates a bioadhesive, film    forming product with sustained duration. Applied as spray or liquid-   ii. testosterone undecanoate or testosterone enantate (hormone    deficiency). Bioadhesive, film forming composition with sustained    duration. May be applied as aerosol- or pump-spray, or as liquid.

Particularly suitable applications of dermatological formulations areanti-infective dermatological bioadhesive depots for protection inenvironments where contact with infective agents is likely (e.g. humanor veterinary surgery, abattoir work, certain types of cleaning etc.).Bioadhesive depots generated from composition of the invention providerobust and sustained protection for the wearer. The compositions withantiinfective agents may also be used in situations where skin sterilityof the wearer is important for the health of others, such as for nursesor doctors visiting multiple patients in hospital, where cross-infectionmust be avoided. A prior coating with a composition of the presentinvention may serve to provide resistance against picking up ofinfectives from one area and thus prevent transmission to another.

In the methods of treatment of the present invention, as well as in thecorresponding use in therapy and the manufacture of medicaments, anactive agent is not always necessary. In particular, lipids,particularly phospholipids such as PC have been implicated as highlybeneficial in themselves for the treatment of certain conditions(including those described herein below). Without being bound by theory,it is believed that suitable lipids, such as those in the formulationsof the present invention, are naturally present in the protective layersover and around many structures of the body, such as the linings of manybody cavities and the contact surfaces of joints. These layers may serveas protection from adhesion and attack by a wide variety of chemical andbiological agents (such as on gastric surfaces and in the lining of theGI tract), may act as lubricants (particularly in joints but cruciallyalso on the linings and membranes surrounding many internal structuressuch as heart and lungs), and may additionally contribute to cell wallrepair by allowing lipid exchange and dilution of undesirablemembrane-bound and membrane-soluble agents. The lipid nature of thecompositions also forms a harmless substrate for unwanted inflammatorylipase enzymes including phospholipases such as phospholipase A₂ (PLA₂).

In an alternative embodiment of the methods of treatment andcorresponding uses of the present invention, suitable actives may beincluded, either as the sole beneficial agent, or to complement theeffect of suitable lipid components. Such actives will typically besuited for the treatment of inflammation and/or irritation, such assteroidal and non-steroidal anti-inflammatory drugs and local immunemodulators. Examples of such agents are well known and many arementioned herein elsewhere. They include, cis-urocanic acid,corticosteroids such as prednisone methylprednisolone andhydrocortisone, and derivatives of nonsteroidal anti-inflammatorycompounds such as benzydamine, paracetamol, ibuprofen and salicylic acidderivatives including acetyl salicylate and 5-amino salicylates. Localinhibitors of inflammatory pathways are also suitable, including theantigen recognition suppressors methotrexate, azathioprine or6-mercaptopurine and phospholipase inhibitors, such as PLA₂ inhibitors.

The pre-formulations of the present invention provide non-lamellarliquid crystalline depot compositions upon exposure to aqueous fluids,especially in contact with body surfaces. As used herein, the term“non-lamellar” is used to indicate a normal or reversed liquidcrystalline phase (such as a cubic or hexagonal phase) or the L3 phaseor any combination thereof. The term liquid crystalline indicates allhexagonal liquid crystalline phases, all cubic liquid crystalline phasesand/or all mixtures thereof. Hexagonal as used herein indicates “normal”or “reversed” hexagonal (preferably reversed) and “cubic” indicates anycubic liquid crystalline phase unless specified otherwise. By use of thepre-formulations of the present invention it is possible to generate anyphase structure present in the phase-diagram of components a and b withwater. This is because the pre-formulations can be generated with awider range of relative component concentrations than previous lipiddepot systems without risking phase separation or resulting in highlyviscous solutions for injection. In particular, the present inventionprovides for the use of phospholipid concentrations above 50% relativeto the total amphiphile content. This allows access to phases only seenat high phospholipid concentrations, particularly the hexagonal liquidcrystalline phases.

For many combinations of lipids, only certain non-lamellar phases exist,or exist in any stable state. It is a surprising feature of the presentinvention that compositions as described herein frequently exhibitnon-lamellar phases which are not present with many other combinationsof components. In one particularly advantageous embodiment, therefore,the present invention relates to compositions having a combination ofcomponents for which an I₂ and/or L₂ phase region exists when dilutedwith aqueous solvent. The presence or absence of such regions can betested easily for any particular combination by simple dilution of thecomposition with aqueous solvent and study of the resulting phasestructures by the methods described herein.

In a highly advantageous embodiment, the compositions of the inventionmay form an I₂ phase, or a mixed phase including I₂ phase upon contactwith water. The I₂ phase is a reversed cubic liquid crystalline phasehaving discontinuous aqueous regions. This phase is of particularadvantage in the controlled release of active agents and especially incombination with polar active agents, such as water soluble activesbecause the discontinuous polar domains prevent rapid diffusion of theactives. Depot precursors in the L₂ phase are highly effective incombination with an I₂ phase depot formation. This is because the L₂phase is a so-called “reversed micellar” phase having a continuoushydrophobic region surrounding discrete polar cores. L₂ thus has similaradvantages with hydrophilic actives.

In transient stages after contact with body fluid the composition cancomprise multiple phases since the formation of an initial surface phasewill retard the passage of solvent into the core of the depot. Withoutbeing bound by theory, it is believed that this transient formation of asurface phase, especially a liquid crystalline surface phase, serves todramatically reduce the “burst/lag” profile of the present compositionsby immediately restricting the rate of exchange between the compositionand the surroundings. Transient phases may include (generally in orderfrom the outside towards the centre of the depot): H_(II) or L_(α), I₂,L₂, and liquid (solution). It is highly preferred that the compositionof the invention is capable forming at least two and more preferably atleast three of these phases simultaneously at transient stages aftercontact with water at physiological temperatures. In particular, it ishighly preferred that one of the phases formed, at least transiently, isthe I₂ phase.

It is important to appreciate that the preformulations of the presentinvention are of low viscosity. As a result, these preformulations mustnot be in any bulk liquid crystalline phase since all liquid crystallinephases have a viscosity significantly higher than could be administeredby syringe or spray dispenser. The preformulations of the presentinvention will thus be in a non-liquid crystalline state, such as asolution, L₂ or L₃ phase, particularly solution or L₂. The L₂ phase asused herein throughout is preferably a “swollen” L₂ phase containingaround 10 wt % or greater of solvent (component c) having a viscosityreducing effect. This is in contrast to a “concentrated” or “unswollen”L₂ phase containing no solvent, or a lesser amount of solvent, orcontaining a solvent (or mixture) which does not provide the decrease inviscosity associated with the oxygen-containing, low viscosity solventsspecified herein.

In one embodiment, a small proportion (e.g. less than 5% by weight) of areinforcing polymer may be added to the formulation.

Upon administration, the pre-formulations of the present inventionundergo a phase structure transition from a low viscosity mixture to ahigh viscosity (tissue adherent) depot composition. Generally this willbe a transition from a molecular mixture, swollen L₂ and/or L3 phase toone or more (high viscosity) liquid crystalline phases such as normal orreversed hexagonal or cubic liquid crystalline phases or mixturesthereof. As indicated above, further phase transitions may also takeplace following administration. Obviously, complete phase transition isnot necessary for the functioning of the invention but at least asurface layer of the administered mixture will form a liquid crystallinestructure. Generally this transition will be rapid for at least thesurface region of the administered formulation (that part in directcontact with air, body surfaces and/or body fluids). This will mostpreferably be over a few seconds or minutes (e.g. up to 30 minutes,preferably up to 10 minutes, more preferably 5 minutes of less). Theremainder of the composition may change phase to a liquid crystallinephase more slowly by diffusion and/or as the surface region disperses.

In one preferred embodiment, the present invention thus provides apre-formulation as described herein of which at least a portion forms ahexagonal liquid crystalline phase upon contact with an aqueous fluid.The thus-formed hexagonal phase may gradually disperse, releasing theactive agent, or may subsequently convert to a cubic liquid crystallinephase, which in turn then gradually disperses. It is believed that thehexagonal phase will provide a more rapid release of active agent, inparticular of hydrophilic active agent, than the cubic phase structure,especially the I₂ and L₂ phase. Thus, where the hexagonal phase formsprior to the cubic phase, this will result in an initial release ofactive agent to bring the concentration up to an effective levelrapidly, followed by the gradual release of a “maintenance dose” as thecubic phase degrades. In this way, the release profile may becontrolled.

Without being bound by theory, it is believed that upon exposure (e.g.to body fluids), the pre-formulations of the invention lose some or allof the organic solvent included therein (e.g. by diffusion and/orevaporation) and take in aqueous fluid from the bodily environment (e.g.moist air close to the body or the in vivo environment) such that atleast a part of the formulation generates a non-lamellar, particularlyliquid crystalline phase structure. In most cases these non-lamellarstructures are highly viscous and are not easily dissolved or dispersedinto the in vivo environment and are bioadhesive and thus not easilyrinsed or washed away. Furthermore, because the non-lamellar structurehas large polar, apolar and boundary regions, it is highly effective insolubilising and stabilising many types of active agents and protectingthese from degradation mechanisms. As the depot composition formed fromthe pre-formulation gradually degrades over a period of hours or days,or even weeks or months (depending upon the nature and site ofapplication), the active agent is gradually released and/or diffuses outfrom the composition. Since the environment within the depot compositionis relatively protected, the pre-formulations of the invention arehighly suitable for active agents with a relatively low biologicalhalf-life (see above).

In an additional aspect of the invention, the topical compositions maybe used to provide a physical barrier on body surfaces, in the absenceof any active agent. In particular, because of the very highbioadherance of the compositions, “barrier” coatings formed by sprayingor application of liquid may be formed from the present compositions soas to reduce contact with potential infective or irritant agents or toreduce soiling of the body surfaces. The robust nature of thecompositions and resistance to washing provide advantageouscharacteristics for such barriers, which could conveniently be appliedas a liquid or by spraying. Without being bound to theory it is believedthat the stability and wear resistance of applied topical compositionsis due to the particular phase transitions of the composition onexposure to aqueous fluid/moisture and the bioadhesion thereof, incombination with the low aqueous solubility of the diacyl lipid buildingblocks.

The formulations, compositions and methods of the invention relating tothe treatment of inflammation or irritation, are particularly suitablefor addressing inflammation and/or irritation in a body cavity.Administration to a body cavity is thus highly suitable in this aspectand will be carried out by a method suitable for the cavity beingtreated. Mouthwashes, for example, may be suitable for oral or buccalcavities, while other parts of the GI tract may be suitably treated byoral formulations, including dispersions and dry pre-formulations, andrectal formulations such as enemas or suppositories. Rinses andpesseries are similarly suitable for vaginal delivery.

The compositions of the present invention are highly suitable fortreating inflammation in a body cavity because of the highly bioadhesivenature of the non-lamellar phase and the resulting long-lasting effects.The inherently soothing and highly biocompatible nature of theconstituents is also important and may pay a passive or active role inthe treatment of inflammation.

The methods of treatment and corresponding uses of the present inventionare thus most applicable to inflammatory diseases and inflammationcaused by, for example, wounding, abrasion, or reaction to aggressivetherapies such as irradiation and/or chemotherapy. Especially suitableare inflammatory diseases affecting at least one body cavity. Diseasesof the GI tract are highly suitable for treatment with the compositionsof the present invention, particularly inflammatory bowel diseaseincluding Crohn's disease and ulcerative collitus and oral inflammationsuch as oral mucositis. Similarly, application to a body cavity duringsurgery may also be used to take advantage of the properties of theformulations. They may thus be directly applied, for example by sprayingor painting, to sooth inflammation resulting from or exposed duringsurgery and also to reduce the tendency of surgically manipulated tissueto “stick” and/or form adhesions/bridges at unwanted sites.

The invention thus particularly provides for a method of treatment of aninflammatory disease (e.g. Crohn's disease, ulcerative collitus or oralmucositis), said method comprising the administration of apreformulation of the present invention either in the absence of anactive agent, or comprising at least one anti-inflammatory oranti-infective active agent such as one selected from corticosteroidssuch as prednisone methylprednisolone and hydrocortisone, andderivatives of nonsteroidal anti-inflammatory compounds such asbenzydamine, paracetamol, ibuprofen and salicylic acid derivativesincluding acetyl salicylate and 5-amino salicylates. Local inhibitors ofinflammatory pathways are also suitable, including the antigenrecognition suppressors methotrexate, azathioprine or 6-mercaptopurineand phospholipase inhibitors, such as PLA₂ inhibitors. Other suitableactives include glutamine, antioxidants such as ascorbate,beta-carrotine, vitamin E, oxypentifylline, Azelastine hydrochloride,allopurinol, chlorhexadine, povidone iodine, nystatin, clotrimazole,polymixin E, tobramycin, amphotericin B, acyclovir, granulocyte colonystimulating factor (G-CSF), granulocyte-macrophage stimulating factor(GM-CSF), cytokines and cytokine inducers/supressors.

Preferably the active agent is selected from corticosteroids, preferablygroup A and/or group B corticosteroids, such as at least one from thegroup consisting of hydrocortisone, hydrocortisone acetate, cortisoneacteate, tixocortol pivalate, prednisolone, methylprednisolone,prednisone, triamcinolone acetonide, triamcinolone alcohol, mometason,amcinonide, budesonide, desonide, fluocinonide, fluocinonide acetonideand halcinonide.

A particularly preferred method and corresponding use is a method forthe treatment of oral mucositis in a human or animal subject (especiallyone in need thereof) by a composition of the present invention(especially comprising preferred combinations of components a), b) andc)) comprising at least one local analgesics or anti-inflammatory agent,especially benzydamine or a derivative thereof. Optionally these may becombined with one or more of the actives indicated above for thetreatment of inflammation, and/or with a topical anaesthetic such aslignocaine, cocaine, diphendramine, or particularly dyclonine HCl.

The Invention will now be further illustrated by reference to thefollowing non-limiting Examples and the attached Figures, in which;

FIG. 1 shows the cumulative release of methylene blue (MB) from a depotformulation comprising PC/GDO/EtOH (45/45/10 wt %) when injected intoexcess water;

FIG. 2 demonstrates the non-linear decrease of pre-formulation viscosityof the depot precursor upon addition of N-methyl pyrrolidinone (NMP) andEtOH;

FIG. 3 displays the in vitro release in excess aqueous phase ofchlorhexidine from a depot formulation comprising PC/GDO/EtOH (36/54/10wt %) containing 50 mg chlorhexidine/g of formulation, corresponding to5% drug load.

FIG. 4. SAXD profiles of SPC/GDO mixtures in excess PBS as a function oflipid weight ratio at 25 (a), 37 (b), and 42° C. (c) prepared at lipidformulation:PBS weight ratio of 1:2. Arrows in (a) show indexing of thereflections from the reversed micellar Fd3m cubic phase. Explanation isgiven in the text.

FIG. 5. SAXD profiles of SPC/GDO/EtOH/PG formulations in excess PBS as afunction of EtOH/PG weight ratio at 25 (a), 37 (b), and 42° C. (c)prepared at lipid formulation:PBS weight ratio of 1:2. SPC/GDO weightratio is 35/65 for all samples.

FIG. 6. Effect of 3 wt % of BZD on the liquid crystalline nanostructureas a function of SPC/GDO weight ratio at lipid formulation:PBS weightratio of 1:2 (a). Effect of BZD concentration on the nanostructure ofSPC/GDO liquid crystalline phases prepared at weight ratio of 35/65 (b).Effect of 3 wt % of BZD on the liquid crystalline nanostructure as afunction of lipid formulation:PBS weight ratio at SPC/GDO weight ratioweight ratio of 35/65 (c). The lipid/EtOH/PG weight ratio was 85/10/5for all samples.

FIG. 7. Time dependence of the mean (±SD) (a) and median (b) values ofpercentage of sites where treatment was present after administration ofSPC/GDO/BZD/EtOH/PG formulations prepared at weight ratios of53.3/28.7/3/10/5 (A), 53.3/28.7/3/15/0 (B), 57.4/24.6/3/10/5 (C), and49.2/32.8/3/10/5 (D). Number of examined sites in mouth=8 (left andright sides of the upper palate, lower palate, inside of the cheek andtongue), number of patients=5.

FIG. 8. Time dependence of the mean VAS score after administration oflipid formulation. Patient question form: evaluation of the analgesiceffect (pain in mouth). Visual analog scale (VAS): 0=no pain, 100=worstimaginable pain. SPC/GDO/BZD/EtOH/PG formulation compositions by weightare: 53.3/28.7/3/10/5 (A), 53.3/28.7/3/15/0 (B), 57.4/24.6/3/10/5 (C),and 49.2/32.8/3/10/5 (D). Number of patients=5.

FIG. 9. Patient reported outcomes regarding taste (a) degree of comfort(b) after dosing of lipid formulations to head and neck cancer patients.Formulation compositions by weight are: 53.3/28.7/3/10/5 (A),53.3/28.7/3/15/0 (B), 57.4/24.6/3/10/5 (C), and 49.2/32.8/3/10/5 (D).Number of patients=5.

FIG. 10. Effect of lidocaine (a), triamcinolone (b), and granisetron (c)on the nanostructure of SPC/GDO/EtOH/PG liquid crystalline phases. Theformulation:PBS weight ratio was 1:2, the SPC/GDO weight ratio was 35/65and lipid/EtOH/PG weight ratio was 85/10/5 for all samples. Theconcentration of API is expressed as wt % of the total formulationweight.

EXAMPLES Example 1 Availability of Various Liquid Crystalline Phases inthe Depot by Choice of Composition

Injectable formulations containing different proportions of phosphatidylcholine (“PC”—Epikuron 200) and glycerol dioleate (GDO) and with EtOH assolvent were prepared to illustrate that various liquid crystallinephases can be accessed after equilibrating the depot precursorformulation with excess water.

Appropriate amounts of PC and EtOH were weighed in glass vials and themixture was placed on a shaker until the PC completely dissolved to forma clear liquid solution. GDO was then added to form an injectablehomogenous solution.

Each formulation was injected in a vial and equilibrated with excesswater. The phase behaviour was evaluated visually and between crossedpolarizes at 25° C. Results are presented in Table 1.

TABLE 1 Formulation PC (wt %) GDO (wt %) EtOH (wt %) Phase in H₂O A 22.567.5 10.0 L₂ B 28.8 61.2 10.0 I₂ C 45.0 45.0 10.0 H_(II) D 63.0 27.010.0 H_(II)/L_(α) L₂ = reversed micellar phase I₂ = reversed cubicliquid crystalline phase H_(II) = reversed hexagonal liquid crystallinephase L_(α) = lamellar phase

Example 2 In Vitro Release of a Water-Soluble Substance

A water-soluble colorant, methylene blue (MB) was dispersed informulation C (see Example 1) to a concentration of 11 mg/g formulation.When 0.5 g of the formulation was injected in 100 ml water a stiffreversed hexagonal H_(II) phase was formed. The absorbency of MBreleased to the aqueous phase was followed at 664 nm over a period of 10days. The release study was performed in an Erlenmeyer flask at 37° C.and with low magnetic stirring.

The release profile of MB (see FIG. 1) from the hexagonal phaseindicates that this (and similar) formulations are promising depotsystems. Furthermore, the formulation seems to give a low initial burst,and the release profile indicates that the substance can be released forseveral weeks; only about 50% of MB is released after 10 days.

Example 3 Viscosity in PC/GDO (6:4) or PC/GDO (3:7) on Addition ofSolvent (EtOH, PG and NMP)

A mixture of PC/GDO/EtOH was manufactured according to the method inExample 1. All, or nearly all, of the EtOH was removed from the mixturewith a rotary evaporator (vacuum, 40° C., 1 h) and the resulting solidmixture were weighed in glass vial after which 2, 5, 10 or 20% of asolvent (EtOH, propylene glycol (PG) or n-methyl pyrrolidone (NMP)) wasadded. The samples were allowed to equilibrate several days before theviscosity was measured at a shear rate of 0.1 s⁻¹ with a Physica UDS 200rheometer at 25° C.

This example clearly illustrates the need for solvent with certain depotprecursors in order to obtain an injectable formulation (see FIG. 2).The viscosity of solvent-free PC/GDO mixtures increases with increasingratio of PC. Systems with low PC/GDO ratio (more GDO) are injectablewith a lower concentration of solvent.

Example 4 Composition and In Vitro Phase Study

The formulations were manufactured according to the method described inExample 1 with compositions according to Table 2. An active substance(peptide), salmon calcitonin (sCT), was added to each formulation to aconcentration of 500 μg sCT/g formulation. The formulations weredesigned as homogenous suspensions for parenteral administration (mixingrequired shortly prior to use since the drug is not completely dissolvedin the PC/GDO/EtOH system).

The phase study in this example is performed in excess of rat serum at37° C. in order to simulate an in vivo situation. Table 2 shows that thesame phases as those in water are formed (compare Table 1).

TABLE 2 PC GDO OA EtOH Phase in Formulation (wt %) (wt %) (wt %) (wt %)rat serum E 18 72 — 10 L₂ F 36 54 — 10 I₂ G 34 51 5 10 I₂ H 54 36 — 10H_(II) I 72 18 — 10 H_(II)/L_(α) OA = Oleic Acid

Example 5 Sterile Filtration of Formulations with Reduced Viscosity

To lower the viscosity with various solvents is sometimes necessary inorder to obtain an injectable formulation and to be able to administratethe system with a regular syringe (see Example 3). Another importanteffect from the viscosity-lowering solvent is that the formulations canbe sterile filtrated.

Formulations E to I in Example 4 were studied in a sterile filtrationtest by using a 0.22 nm filter (before addition of the activesubstance). Formulations E to H were successfully filtrated, butformulation I failed since the viscosity was too high. An asepticmanufacturing procedure was therefore needed for this formulation.

Example 6 Preparation of Depot Precursor Compositions with VariousSolvents

Depending on composition of the formulation and the nature andconcentration of active substance certain solvents may be preferable.

Depot precursor formulations (PC/GDO/solvent (36/54/10)) were preparedby with various solvents; NMP, PG, PEG400, glycerol/EtOH (90/10) by themethod of Example 1. All depot precursor compositions were homogeneousone phase solutions with a viscosity that enabled injection through asyringe (23G—i.e. 23 gauge needle; 0.6 mm×30 mm) After injectingformulation precursors into excess water a liquid crystalline phase inthe form of a high viscous monolith rapidly formed with NMP and PGcontaining precursors. The liquid crystalline phase had a reversed cubicmicellar (I₂) structure. With PEG400, glycerol/EtOH (90/10) theviscosification/solidification process was much slower and initially theliquid precursor transformed to a soft somewhat sticky piece. Thedifference in appearance probably reflects the slower dissolution ofPEG400 and glycerol towards the excess aqueous phase as compared to thatof EtOH, NMP and PG.

Example 7 Preparation of Depot Composition Containing Benzydamine

Benzydamine is a non-steroidal antiinflammatory drug and is extensivelyused as a topical drug in inflammatory conditions.

1 g of a depot formulation containing 1.5 mg benzydamine was prepared bydissolving the active substance in a mixture of PC/GDO/EtOH (36/54/10)prepared as described in Example 1. The depot composition was stableagainst crystallization during storage at 25° C. for at least two weeks.Equilibration of the formulation precursor with excess water resulted ina high viscous monolithic liquid crystalline phase (I₂ structure).

Example 8 Robustness of the Behaviour of the Formulation AgainstVariations in the Excipient Quality

Depot precursor formulations were prepared with several different GDOqualities (supplied by Danisco, Dk), Table 3, using the method ofExample 1. The final depot precursors contained 36% wt PC, 54% wt GDO,and 10% wt EtOH. The appearance of the depot precursors was insensitiveto variation in the quality used, and after contact with excess water amonolith was formed with a reversed micellar cubic phase behaviour (I₂structure).

TABLE 3 Tested qualities of GDO. Monoglyceride Diglyceride TriglycerideGDO quality (% wt) (% wt) (% wt) A 10.9 87.5 1.6 B 4.8 93.6 1.6 C 1.097.3 1.7 D 10.1 80.8 10.1 E 2.9 88.9 8.2 F 0.9 89.0 10.1

Example 9 Preparation of Depot Composition Containing Saturated PC(Epikuron 200SH)

Depot precursor formulations were prepared with various amounts PCcomprising saturated hydrocarbon chains by addition of Epikuron 200SHdirectly to a mixture of PC/GDO/EtOH, prepared as for Example 1. Theformulations are shown in Table 4. All precursor formulations werehomogenous one phase samples in RT, while they became more viscous withincreasing amount Epikuron 200SH. Injecting the depot precursor intoexcess water gave a monolith comprising a reversed miceller cubic (I₂)structure. Monoliths formed from samples containing higher amounts ofEpikuron 200SH became turbid, possibly indicating segregation betweenEpikuron 200SH and the other components upon exposure to water andformation of the 12 phase.

TABLE 4 Depot composition containing saturated PC Saturated PC, EpikuronPC GDO EtOH Formulation 200SH (% wt) (% wt) (% wt) (% wt) G1 3.9 34.651.9 9.6 G2 7.0 33.5 50.2 9.3 G3 14.3 30.8 46.3 8.6

Example 10 Bioadhesive Spray of Depot Precursor Formulation

A pump spray bottle was found to be a convenient way to apply theformulation topically, e.g. to the skin or the oral mucosa.

A depot precursor formulation prepared as in Example 1 (36% wt PC, 54%wt GDO, and 10% wt EtOH) was sprayed with a pump spray bottle onto theskin and oral mucosa. A film with solid mechanical properties formedshortly after application.

Example 11 Robustness of a Topical Film

After applying the depot precursor formulation, as described in Example10, (36% wt PC, 54% wt GDO, and 10% wt EtOH) to the skin, the appliedformulation was exposed to flushing water (10 L/min) for 10 minutes. Theformulation showed excellent bioadhesive properties and resistanceagainst rinsing and no loss of the formulation could be discerned.

Example 12 Formation of Cubic Phase with Solid Properties after Exposureof Depot Precursor Formulation to Air

After exposing a depot precursor formulation prepared as described inExample 1 (36% wt PC, 54% wt GDO, and 10% wt EtOH) to air (RT, relativehumidity 40%) for at least 3 hours, a solid cubic phase was formed. Thisformation of a cubic phase structure demonstrates that a topical filmwill acquire bulk non-lamellar depot properties after applicationwithout the need for direct exposure to excess aqueous fluid.

Example 13 Formulation to Treat Periodontitis or Perimplantitis

In order to treat periodontitis or perimplantitis an antibacterialformulation is injected in the periodontal pocket, and a prolongedeffect of the formulation is normally desired. 100 μL of a formulationas prepared in Example 1, with the addition of the antibioticchlorohexidine (PC/GDO/EtOH/chlorhexidine (35/53/10/2)), is injected viaa syringe into a rat peridontal pocket. The injected composition isobserved to transform from the low viscous formulation, and whichinitially spreads out to fill voids, to form a solid mass by uptake ofgingival fluids. An antibacterial depot system is thus provided.

Chlorhexidine remains at clinically effective levels (MIC 125 μg/ml) inthe GCF of the periodontal pockets for over 1 week. The depot system iscompletely degraded by enzymes within 7 to 10 days and does not need tobe removed.

Example 14 Alternate Antibacterial Formulation to Treat Periodontitis orPerimplantitis

An alternate antibacterial formulation was provided by a formulationprepared as described in Example 1 and containing the antibacterialdetergent Gardol (Glycine, N-methyl-N-(1-oxododecyl)-, sodium salt)(PC/GDO/EtOH/Gardol (34/51/10/5)). This formulation is injected into therat periodontal pocket.

Gardol is observed to remain at clinically effective levels in the GCFof the periodontal pockets for a prolonged period (several days). Thedepot system is completely degraded by enzymes within 7 to 10 days anddid not need to be removed.

Example 15 Adhesion of the Formulation to High Energy Surfaces

In order to treat perimplantitis, adhesion not only to biologicalsurfaces but also to high energy surfaces such as a gold or titaniumimplant is important. It is also important that the formulation adheresto ceramic and plastic surfaces.

A formulation (PC/GDO/EtOH (36/54/10)) as prepared in Example 1 wasapplied to various surfaces in the oral cavity. The composition showedexcellent adhesion to ceramic, plastic, gold, as well as to a normaltooth surface and could not be rinsed away by excess aqueous fluid. Thedepot resulting from the composition stayed at the site in the oralcavity where it was applied for at least 6 h.

Example 16 Bioadhesive Sustained Release Formulation of Sodium Fluoridefor Use on the Teeth

Fluoride containing compounds are often needed to oppose caries attackand a bioadhesive formulation precursor with depot effect was preparedas indicated in Example 1 from a mixture of PC/GDO/EtOH/sodium fluoride(35/53/10/2). The formulation was a dispersion of sodium fluoride sinceit could not be dissolved in the precursor. The liquid formulation wasapplied to the teeth with the aid of a brush. By uptake of saliva theformulation solidified and formed a depot providing sustained release ofsodium fluoride for an extended period (several hours).

Example 17 Oral Cavity Spray Depot Composition

To be suitable as a topical depot system in the oral cavity themechanical properties of the system was adjusted by decreasing thePC/GDO ratio.

A mixture containing PC/GDO/EtOH (27/63/10) was prepared according toExample 1. A drop of patent blue was added to visualize the formulationafter application. About 300 μl of the formulation was sprayed into theoral cavity with pump spray bottle. Shortly after application theformulation viscosified/solidified since it underwent a phasetransformation by uptake of aqueous fluid (saliva) and loss of solvent(EtOH). The formulation had excellent bioadhesion to keritinizedsurfaces such as the hard palate and the gum. Here the film lasted forseveral hours despite saliva secretion and mechanical wear by thetongue. At soft mucosal surfaces the duration was much shorter(minutes).

Example 18 Oral Cavity Liquid Depot Composition

To be suitable for application with a pipette to the oral cavity thesolidification/viscosification of the formulation has to be delayedrelative to the spray formulation. This is to allow the formulation tobe conveniently distributed with the tongue to a thin film in the oralcavity after application.

Propylene glycol (PG) and EtOH were added to a formulation prepared asin Example 1, to the final composition PC/GDO/EtOH/PG (24/56/10/10). 300μl of the formulation was conveniently applied with a pipette to theoral cavity and distributed with the tongue to a thin film in the oralcavity. After about 20 seconds the viscosification of the formulationstarted since it underwent a phase transformation by uptake of aqueousfluid (saliva) and loss of solvent (EtOH and PG). After about one minutethe solidification/viscosification appeared to be finished. Theformulation had excellent bioadhesion to keritinized surfaces such asthe hard palate and the gum. Here the film lasted for several hoursdespite saliva secretion and mechanical wear by the tongue. At softmucosal surfaces the duration was much shorter (minutes).

Example 19 Bioadhesive Depot for Nails

The mixture in Example 18 was sprayed to the nail bed and in between thetoes. The formulation solidifies/viscosifies slowly by uptake of aqueousfluids (cf. sweat). The solidification can be speeded up by adding waterafter spray application. The formulation had excellent bioadhesiveproperties and had a duration for several hours.

Example 20 Loading Capacity of the Bioactive Agent Benzydamine in theFormulation Precursors

Formulations with compositions as specified in Table 5 were preparedusing the method in Example 1. An excess amount of benzydamine (50 mg)was added to 0.5 g of the formulations. The vials were placed on ashaker at 15° C. for three days after which the solutions were filteredthrough a filter (0.45 μm) to get rid of crystals of undissolvedbenzydamine. The benzydamine concentration in each formulation wasdetermined with reversed phase gradient HPLC and UV detection at 306 nmand the results are given in Table 5.

TABLE 5 Composition Benzydamine GDO/PC(Lipoid S100)/EtOH concentrationin formulation 67.5/22.5/10 3.4% 63/27/10 3.2% 58.5/31.5/10 3.3%60/20/20 4.0% 56/24/20 4.5% 52/28/20 4.3%

Example 21 Compositions Containing PC and Tocopherol

Depot precursor formulations were prepared with several differentPC/α-tocopherol compositions using the method of Example 1 (PC was firstdissolved in the appropriate amount of EtOH and thereafter α-tocopherolwas added to give clear homogenous solutions).

Each formulation was injected in a vial and equilibrated with excesswater. The phase behaviour was evaluated visually and between crossedpolarizes at 25° C. Results are presented in Table 6.

TABLE 6 α-tocopherol PC Ethanol Phase in excess H₂O 2.25 g 2.25 g 0.5 gH_(II)  2.7 g  1.8 g 0.5 g H_(II)/I₂ 3.15 g 1.35 g 0.5 g I₂  3.6 g  0.9g 0.5 g I₂/L₂

Example 22 In Vitro Release of Water-Soluble Disodium Fluorescein

A water-soluble colorant, disodium fluorescein (Fluo), was dissolved ina formulation containing PC/α-tocopherol/Ethanol (27/63/10 wt %) to aconcentration of 5 mg Fluo/g formulation. When 0.1 g of the formulationwas injected in 2 ml of phosphate buffered saline (PBS) a reversedmicellar (I₂) phase was formed. The absorbency of Fluo released to theaqueous phase was followed at 490 nm over a period of 3 days. Therelease study was performed in a 3 mL vial capped with an aluminiumfully tear off cap at 37° C. The vial was placed on a shaking table at150 rpm.

The release of Fluo from the PC/α-tocopherol formulation (see Table 7)indicates that this (and similar) formulations are promising depotsystems. Furthermore, the absence of a burst effect is noteworthy, andthe release indicates that the substance can be released for severalweeks to months; only about 0.4% of Fluo is released after 3 days.

TABLE 7 % release (37° C.) Formulation 24 h 72 h PC/α-tocopherol/EtOH:<0.1* 0.43 27/63/10 wt % *Release below detection limit of theabsorbance assay

Example 23 Formulations of the Analgesic/Antiinflammatory Benzydamine

Formulations were prepared as in Example 1 by mixing benzydamine with amixture of GDO, PC, ethanol and optionally PG/AP in the followingproportions.

Formulation BZD GDO PC EtOH PG AP 1 3.0 53.3 28.7 10.0 5.0 0.01 2 3.053.3 28.7 15.0 0 0.01 3 3.0 57.4 24.6 10.0 5.0 0.01 4 3.0 49.2 32.8 10.05.0 0.01 where BZD is benzydamine, EtOH is ethanol, PC is LIPOID S100soybean phosphatidylcholine, GDO is glycerol dioleate, PG is propyleneglycol, and AP is ascorbyl palmitate.

All formulations are low viscosity liquids which generate liquidcrystalline phase compositions upon exposure to aqueous conditions.

Example 24 Fentanyl Nasal Formulation

Formulations were prepared as in Example 1 by mixing the narcoticanalgesic fentanyl with a mixture of GDO, PC, ethanol and optionally PGin the following proportions.

Formulation Fentanyl PC GDO EtOH PG 1 0.05 34 51 10 5 2 0.05 36 54 10 —3 0.05 42 43 10 5 4 0.05 45 45 10 — 5 0.15 34 51 10 5 6 0.15 36 54 10 —7 0.05 30 45 15 10  8 0.15 30 45 15 10  where EtOH is ethanol, PC isLIPOID S100 soybean phosphatidylcholine, GDO is glycerol dioleate, andPG is propylene glyco

All formulations are low viscosity liquids suitable for administrationby nasal spray, which generate liquid crystalline phase compositionsupon exposure to aqueous conditions.

Example 25 Diazepam Nasal Formulation

Formulations were prepared as in previous examples by mixing thebenzodiazepine antianxiety agent diazepam with a mixture of GDO, PC,ethanol and optionally PG in the following proportions.

Formulation Diazepam PC GDO EtOH PG 1 5 32 48 10 5 2 5 34 51 10 — 3 1037 38 10 5 4 10 40 40 10 — 5 10 30 45 10 5 6 10 32 48 10 — 7 10 26 39 1510  8 10 30 45 15 — where EtOH is ethanol, PC is LIPOID S100 soybeanphosphatidylcholine, GDO is glycerol dioleate, and PG is propyleneglycol

All formulations are low viscosity liquids suitable for administrationby nasal spray, which generate liquid crystalline phase compositionsupon exposure to aqueous conditions.

Example 26 Acne Formulations with Clindamycin

Formulations were prepared as in previous examples by mixing thesemisynthetic antibiotic clindamycin (free base or salt) with a mixtureof GDO, PC, ethanol and PG in the following proportions (by weight).

Clindamycin Formulation HCl PC GDO EtOH PG 1 1 30 54 10 5 2 2 29 54 10 53 1 34 50 10 5 4 2 33 50 10 5

Clindamycin Formulation base PC GDO EtOH PG 5 1 30 54 10 5 6 2 29 54 105 7 1 33 54 2 10 8 2 32 54 2 10

The resulting preformulations are low viscosity liquids which, afterapplication resistant to water, sweat, etc. The formulation are appliedlocally on the skin as a gel or by spraying and are bioadhesive withgood film-forming properties.

Example 27 Further Examples of Viscosity in PC/GDO Mixtures on Additionof Co-Solvent

Mixtures of PC/GDO and co-solvent were prepared according to the methodsof Example 1 and Example 3 in the proportions indicated in the tablebelow.

The samples were allowed to equilibrate for several days beforeviscosity measurements were performed using a Physica UDS 200 rheometerat 25° C.

PC/GDO EtOH/ Glycerol/ H₂O/ Viscosity/ Sample (wt/wt) wt % wt % wt %mPas 1 50/50 3 — — 1900 2 50/50 5 — — 780 3 50/50 7 — — 430 4 50/50 8 —— 300 5 50/50 10 — — 210 6 50/50 15 — — 100 7 45/55 3 — — 1350 8 45/55 5— — 540 9 45/55 7 — — 320 10 45/55 8 — — 250 11 45/55 10 — — 150 1245/55 15 — — 85 13 40/60 3 — — 740 14 40/60 5 — — 400 15 40/60 7 — — 24016 40/60 8 — — 200 17 40/60 10 — — 130 18 40/60 15 — — 57 19 40/60 — 10— 8 * 10⁶ 20 40/60 — — 3 2.5 * 10⁸   21 40/60 — — 5 4 * 10⁷

This example further illustrates the need for a solvent with viscositylowering properties in order to obtain injectable formulations. Themixtures containing glycerol (sample 19) or water (samples 20 and 21)are too viscous to be injectable at solvent concentrations equivalent tothe samples containing EtOH (compare with samples 13, 14 and 17).

Example 28 Sunscreen Formulations

Formulations were prepared as in Example 1 by mixing each of several UVabsorbing/scattering agents with a mixture of GDO, PC, and ethanol inthe following proportions (by weight)

Formu- Tioveil Spectraveil Solaveil Tioveil lation PC GDO EtOH CM FINCT-100 50 MOTG 1 38 42 5 — — — 15 2 38 42 5 — — 15 — 3 37 38 5 15 5 — —

Where TIOVEIL CM (Uniqema) comprises Cyclomethicone (and) TitaniumDioxide (and) Dimethicone Copolyol (and) Aluminium Stearate (and)Alumina, SPECTRAVEIL FIN (Uniqema) comprises Zinc Oxide (and) C12-15Alkyl Benzoate (and) Polyhydroxystearic Acid, SOLAVEIL CT-100 (Uniqema)comprises C12-15 Alkyl Benzoate (and) Titanium Dioxide (and)Polyhydroxystearic Acid (and) Aluminum Stearate (and) Alumina, andTIOVEIL 50 MOTG (Uniqema) comprises Titanium Dioxide (and)Caprylic/Capric Triglyceride (and) Mineral Oil (and) PolyhydroxystearicAcid (and) Aluminum Stearate (and) Alumina.

The resulting formulation precursors show low viscosity upon formulationand are readily applied by pump spray. Upon contact with body surfaces aresilient UV protective layer is formed.

Example 29 Chlorhexidine Periodontal Depots

Formulations were prepared as in Example 1 by mixing the antiinfectiveagent chlorhexidine digluconate with a mixture of GDO, PC, and ethanolin the following proportions (by weight)

TABLE Chlorhexidine digluconate depot formulation compositions.Chlorhexidine Formulation digluconate PC GDO EtOH A 5 34 51 10 B 5 36 545 C 7 33 50 10 D 10 32 48 10 E 15 30 45 10

The chlorhexidine depot preformulations have low viscosity and areeasily administered to the periodontal pocket. The compositions providebetter distribution and spreading of the active substance throughout theperiodontal pocket when compared to current products, such asPeriochip®.

The depot formed after application gives protection against re-infectionof the pocket. The depot also has excellent bioadhesive properties andsticks to mucosal, teeth and bone surfaces.

Release of chlorhexidine digluconate from 250 mg Formulation A (seeabove) in 0.9% aqueous NaCl (500 ml) was studied. The formulation washeld in a cylindrical metal cup which was placed in a teflon holder atthe bottom of a standard USP release bath. The contact area between theformulation and surrounding saline solution was 2.4 cm², and thesolution was stirred by paddle at 100 rpm.

The release curve shown in FIG. 3 demonstrates the sustained andessentially uniform release of chlorhexidine from the formulation over aperiod of 24 hours.

Example 30 Topical Formulation with a NSAID

Diclofenac sodium is a nonsteroidal anti-inflammatory drug (NSAID). Itbelongs to the phenylacetic acid group and is used in inflammatoryconditions of various etiologies, degenerative joint disease and manyother painful conditions.

A formulation for topical administration containing diclofenac sodiumwas prepared by first preparing a placebo formulation.

Composition of placebo formulation Excipient Abbreviation Concentration(%) Phosphatidyl choline (from soy SPC 45.0 bean) Glycerol dioleate GDO45.0 Etanol 99.5% EtOH 10.0

Diclofenac sodium to a concentration of 5% was dissolved in the placeboformulation. The resulting oily liquid was slightly yellowish,transparent, and had a low viscosity.

Example 31 Formation of Liquid Crystalline Phase

One drop of the diclofenac sodium containing formulation in Example 30was added to 3 ml aqueous saline solution with a pipette. A cohesiveliquid crystalline phase formed.

Example 32 Formation of Rigid Film In Situ

One drop of the diclofenac sodium containing formulation in example 30was applied to the skin on the arm of a healthy volunteer and smearedout to a thin film covering an area of about 2-4 cm². Shortly afterapplication the liquid formulation transformed to a much more rigid filmby uptake of small amounts of water from the skin and/or the air.

Example 33 Improving Spray Pattern by Lowering Viscosity

A placebo formulation with the composition as given in the Table inExample 30 was filled in a standard pump-spray bottle. After priming thepump with formulation the formulation could be applied to the skin witha sub-optimal spray-pattern. By diluting the formulation further withEtOH the viscosity of the formulation decreased and at an EtOHconcentration corresponding to about 25% the formulation could beapplied as a mist to the skin. Spaying the formulation to the skin onthe arm of a healthy volunteer resulted in formation of a rigid filmafter evaporation of EtOH and uptake of small amounts of water from theskin and/or the air.

Example 34 Improving Spray Pattern by Using a Compression Pump Device

A placebo formulation with the composition as given in the Table inExample 30 was filled in a standard compression pump bottle. This devicegave a good mist/aerosol and spray pattern. Spaying the formulation tothe skin on the arm of a healthy volunteer resulted in formation of arigid film after uptake of small amounts of water from the skin and/orthe air.

Example 35 Use of Pressure Driven Device

A placebo formulation with the composition as given in the Table inExample 30 was filled in a pressure driven spray-device either with ahydrocarbon propellant or with HFC-134a as propellant, respectively.Both propellants were found to form low-viscous homogeneous mixtureswith the formulation. Spaying the formulation to the skin on the arm ofa healthy volunteer resulted in rapid formation of a rigid film afteruptake of small amounts of water from the skin and/or the air.

Example 36 Spraying Formulation with Very Low Concentration of EtOH

A formulation with the composition as given in the table below wasprepared by evaporating EtOH from the placebo formulation with thecomposition as given in the Table in Example 30 with the aid of a rotaryevaporator (vacuum, 40° C.). The resulting formulation had a highviscosity but when mixed with propellant (hydrocarbon propellant orHFC-134a) and filled in a spray bottle the formulation could be sprayedto the skin on the arm of a healthy volunteer where a rigid film formedafter uptake of small amounts of water from the skin and/or the air.

Composition of placebo formulation Excipient Abbreviation Concentration(%) Phosphatidyl choline (from soy SPC 49.0 bean) Glycerol dioleate GDO49.0 Etanol 99.5% EtOH 2.0

Example 37 Targeting to Different Surfaces by Varying the Composition ofthe Formulation

By varying the PC/GDO ratio in the formulation duration of theformulation at different places in the oral cavity could be adjusted. Aformulation with the composition PC/GDO/EtOH (36/54/10) has a preferencefor adherence to hard surfaces, such as teeth, while a formulation withthe composition PC/GDO/EtOH (27/63/10) was found to be better suited forthe upper palate.

Example 38 Formation of a Liquid Crystalline Phase from Precursors withVarious Solvent Mixtures

To improve solubility of active substance in the precursors it may beuseful to change solvent in the formulation. A number of differentsolvent mixtures were used in the formulation precursors (see Table) andtheir ability to form a liquid crystalline phase after contacting themwith excess aqueous solution was investigated. One drop of eachformulation was added to 3 ml aqueous saline solution with a pipette.Independent of the solvent (mixture) used a cohesive liquid crystallinephase formed.

Composition of formulations Excipients Composition (wt %) PC/GDO/EtOH45/45/10 PC/GDO/EtOH/NMP 45/45/5/5 PC/GDO/EtOH/propylene-carbonate45/45/5/5 PC/GDO/EtOH/dimethyl-isosorbide 45/45/5/5PC/GDO/EtOH/dimethyl-acetamide 45/45/5/5 PC/GDO/EtOH/ethyl-acetate45/45/5/5

Example 39 Topical Formulation with Testosterone Enanthate

A topical formulation containing 2% testosterone enanthate was preparedby mixing the components in the Table below. Shortly after applying theliquid formulation to the skin it transformed to a much more rigid filmby uptake of small amounts of water from the skin and/or the air.

Composition of topical formulation with testosterone enanthate ComponentAmount (g) Composition (wt %) Testosterone enanthate 0.060 2.00 SoyPhosphatidyl 1.323 44.10 Choline Glycerol Dioleate 1.323 44.10 Ethanol0.294 9.80

Example 40 Further Studies 40.1—Materials

Excipients used in the experiments of this Example were soyphosphatidylcholine (SPC) denoted as 5100 (Lipoid GmbH, Ludwigshafen,Germany); glycerol dioleate (GDO) denoted as Rylo DG 20 Pharma (Danisco,Aarhus, Demark); and polyoxyethylene (20) sorbitan monooleate denoted aspolysorbate 80, P80 (Croda, U.K.) Lidocaine (LID) (purity 98%, Lot068K0112) and triamcinolone acetonide (TCA) (purity 99.5%, Lot 115K1393)were purchased from Sigma-Aldrich. Granisetron hydrochloride (GRN)(purity 99.9%, Batch No 20090914) was obtained from LGM Pharma(Nashville, Tenn.). Benzydamide hydrochloride (BZD) was obtained fromApoteksbolaget AB (Umeå, Sweden). Absolute ethanol (99.5 vol %) fromSolveco AB (Rosersberg, Sweden), propylene glycol (PG) fromApoteksbolaget AB (Umea, Sweden), sterile water from B. Braun Medical AB(Bromma, Sweden) and phosphate buffered saline (PBS) tablets yielding0.01 M phosphate buffer, 0.137 M NaCl, 0.002 M KCl, pH 7.4 fromSigma-Aldrich were used for the preparation of lipid formulations andliquid crystalline (LC) phases. All other solvents and reagents were ofanalytical grade and were used as received.

40.2—Preparation of Lipid-Based Compositions

Non-aqueous lipid formulations were prepared by mixing appropriateamounts of excipients (for example SPC and/or GDO) and co-solvents (e.g.ethanol and/or propylene glycol (PG)). The samples were then placed on aroller mixer at room temperature for few hours until mixed completely.Active pharmaceutical ingredient (API)-containing formulations wereprepared by weighing appropriate amounts API and non-aqueous lipidformulation and placing on a roller mixer at room temperature for 12hours until homogeneous mixture was obtained. In this Example theconcentration of API is always expressed as wt % of the totalformulation weight. Prepared lipid compositions were kept at roomtemperature until further use.

Formulations used in the clinical pilot study (Example 40.7) weremanufactured by Apoteket Production and Laboratories AB, Umeå, Sweden,according to Good Manufacturing Practice standards. Study formulationswere divided into 3.5-ml aliquots in glass vials sealed with rubbercaps. The study formulations were labelled with: “For clinical study,”patient number, treatment day, expiry date, storage instructions,investigator name, manufacturer name and sponsor name. ApoteketProduction and Laboratories AB also manufactured an ethanol solution ofPatent Blue (E 131) (PtB) (Batch No. 1934084) that was added to thestudy formulations before administration for visualisation purposes. Theformulations and stain solution were stored at room temperature (15-25°C.) in the dark at the hospital pharmacy until delivered to the site. Onthe day of administration, 12 μl of the Patent Blue solution (10% w/w inethanol) per ml of study formulation was added at the hospital pharmacyin Lund.

Phase Behavior and Nanostructure of Lipid Compositions

Aqueous phase behavior was studied by hydrating non-aqueous lipidformulations with phosphate buffered saline (0.01 M phosphate bufferwith 0.137 M NaCl and 0.002 M KCl, pH 7.4) at various weight ratios:2:1, 1:1, 1:2 and 1:9. After brief vortexing, samples were left toequilibrate at room temperature for 1 week before X-ray diffractionmeasurements.

The nanostructure of hydrated lipid samples was studied usingsynchrotron small angle X-ray diffraction (SAXD). Measurements wereperformed at the 1911 beam-line at MAX-lab (Lund University, Sweden),using a Pilatus 1M 165 mm CCD detector with a resolution of 981×1043pixels at a pixel size of 0.172 mm. The lipid samples were mountedbetween kapton windows in a steel sample holder at a sample-to-detectordistance of 1312 mm. Diffractograms were recorded at the X-raywavelength of 0.91 Å and a beam size of 0.25×0.25 mm (full width at thehalf maximum) at the sample. Temperature control within 0.1° C. wasachieved using computer controlled Julabo heating circulator F12-MC(Julabo Labortechnik GMBH, Seelbach, Germany). When temperature effectswere studied, the experiments were performed successively at 25° C., 37°C. and 42° C. with a 3-min exposure time at each temperature and a waitof 10 minutes between temperature steps. The resulting CCD images wereintegrated and analysed using the Fit2D software provided by Dr. A.Hammersley (http://www.esrf.fr/computing/scientific/FIT2D). Silverbehanate calibrated sample-to-detector distance and detector positionswere used.

40.3—Non-Clinical Assessment of Tolerability of SPC/GDO Formulations inSyrian Hamsters.

Three non-clinical studies in Syrian hamsters were performed assessinglocal tolerability of SPC/GDO formulations (Camurus A B. Unpublishedresults, 2005, 2011a, and 2011b). The Syrian hamster was selected asthis species is accepted as a suitable model (in compliance with ISO10993-11) for the intended clinical dosing route of Episil® on the oralmucosa. A collar was placed around the neck to permit normal feeding andrespiration but preventing the animal from storing food in the pouches,which could damage the cheek pouch mucosa. Prior to administration, thecollar was removed and the pouch was rinsed with physiological salinesolution. The test items were applied onto the left cheek pouch whilethe right pouch was left untreated as intra-individual controls. Localtolerability was assessed by visual inspection and scoring using anotoscope prior to each administration and at termination examination,and by histopathology; a 7-day oral irritation study (N=24 females), a15-day pilot feasibility study (N=10 females) to determine the maximumfeasible dose volume and regimen by assessment of bioadhesion, andevaluation of local irritation, and a 90-days subchronic systemictoxicity study (N=40 females and 40 males), applying the maximumfeasible dose determined in the pilot study.

The 7-day study evaluated local irritation by macroscopic andmicroscopic examination of the oral cheek pouches following dailyapplication of 0.5 mL of 4 different test formulations.

In the 15-day study, mucosal adhesion of Episil® dyed with Patent blueafter daily and twice-daily exposure onto cheek pouches of up to 0.45 mL(3 sprays of 0.15 mL) was evaluated by otoscopic inspection prior toeach administration. Local irritation was assessed by visual inspectionand scoring prior to each administration, macroscopic evaluation andscoring at termination and histopathology of the cheek pouches.

The 90-day study was designed to meet the requirements for determiningthe biocompatibility of a surface-contacting medical device compliantwith ISO10993-1. The animals were divided into two treatment groups(Group 1 and Group 2) each including three different termination groups;5+5 interim animals treated for 28 days, 10+10 main study animalstreated for 90 days, and 5+5 recovery animals treated for at least 90days followed by a 14-day recovery period. The animals in Group 2received 1 spray of 0.15 ml Episil® in the left cheek pouch twice daily.The animals in Group 1, the control group, were treated in a similar wayusing sterile saline. The study design included assessment ofsub-chronic systemic toxicity (in compliance with ISO10993-11) as wellas assessment of oral irritation by histopathological evaluation (incompliance with ISO10993-10) after the twice daily dosing of Episil®.Twice daily administration was chosen as this was shown to give apermanent exposure to Episil® in the cheek pouches of the Syrianhamsters in the pilot feasibility study. Local tolerability was assessedby macroscopic evaluation of the cheek pouch mucosa using an otoscopeprior to each administration and as termination examination, and byhistopathology. Irritation index for each treatment groups wasdetermined as the average microscopic score for the untreated controlcheek pouch subtracted from the average cheek pouch score for thetreated cheek pouch. Systemic toxicity was assessed by body weightchange, clinical signs, clinical pathology, necropsy evaluations, organand tissue weights, and histopathology of cheek pouches and any grosslesions.

Compositions of the formulations used in all three nonclinical studiesare given in Table 8.

40.4—Clinical Assessment of Intraoral Bioadhesion in Head and NeckCancer Patients

To access the bioadhesive properties of PC/GDO-based formulations suchas Episil®, a cross-over, double-blind, randomized pilot study of 4FluidCrystal® formulations, with varying SPC/GDO ratio and solventcompositions, was conducted in head and neck cancer (HNC) patientsundergoing radiotherapy (n=5) at Lund University Hospital. The trial wasconducted in accordance with the Declaration of Helsinki and itsrevisions as well as with the valid local and national laws of Sweden;with the International Conference on Harmonisation (ICH) HarmonisedTripartite Guideline for Good Clinical Practice (E6) issued in July1996; and with the relevant European Commission Directives. All patientsgave written informed consent prior to enrollment. The patients werescreened and randomised during week 3-4 of radiotherapy to receive onestudy formulation on each day (A, B, C or D in Table 9) during 4consecutive days (Days 1-4) according to a 4-way crossover schedule,allowing a washout night between treatments. On each treatment day,before application of study medication, the status of the oral cavitywas checked and the presence of ulcers was recorded. After eachapplication of the formulation, the oral cavity was examined forpresence of the formulation on eight areas in the mucosa; four in thepalate, one on the inside of each cheek and one on each side of thetongue.

The visual evaluation of the study formulations was carried out by thedental hygienist 5 min., 30 min., 1 hour, 2 hours and 3 hours afterapplication of each formulation. At each interval, the patient was alsoasked to assess the acceptability of the formulation, such asirritation, taste and degree of comfort. In addition, the patient wasasked to estimate the analgesic effect of the study formulations (pain)using a 100 mm visual analogue scale (VAS). Adverse events were recordedon each treatment day and at the follow-up visit on Day 5. The totalstudy duration for all patients was less than 2 weeks. The double-blinddesign of the study assured a non-biased evaluation and the crossoverdesign made it possible to compare the various formulations within thesame patient. No control groups were used in the study.

40.5—Results and Discussion Phase Behavior and Structural Properties ofSPC/GDO LC Phases

The phase behavior of mixtures of SPC and GDO in water is rich inpolymorphism (Oradd et al., 1995; Tiberg et al., 2012). As mentioned,the lipid ratios of SPC/GDO mixtures are expressed in wt %. At 25° C.with increasing GDO content, fully hydrated SPC/GDO mixtures in waterform the following phase sequence: lamellar (L_(α))→reversed 2Dhexagonal (H₂, up to 62.5/37.5)→reversed micellar cubic of Fd3m spacegroup (50/50-45/55)→reversed 3D hexagonal of P6₃/mmc space group(42/58-40/60)→unresolved “intermediate” (39/61-37/63)→Fd3m(37/63-22.5/77.5)→reversed micellar solution (L₂, from 20/80).

We investigated the aqueous phase behavior of SPC/GDO mixtures preparedat weight ratios of 40/60, 35/65 and 30/70 in more detail. To moreclosely mimic in vivo conditions, experiments were performed in morephysiologically relevant solvent environment and at appropriatetemperatures. PBS is here considered as a physiologically relevantsolvent since the pH, viscosity and composition closely mimics that of,for example, saliva. FIG. 4 shows SAXD profiles of the fully hydrated LCaggregates formed in SPC/GDO mixtures in large excess of PBS (pH 7.4) asa function of lipid weight ratio and temperature. At 25° C. and atSPC/GDO weight ratios of 30/70 and 35/65, the lipid mixtures formreversed micellar cubic phase. This is nicely shown by the location ofthe first 15 Bragg peaks at relative positions in ratios of√3:√8:√11:√12:√16:√19:√24:√27:√32:√35:√40:√43:√44:√48:√51, which can beindexed as the (111), (220), (311), (222), (400), (331), (422),(511/333), (440), (531), (620), (533), (622), (444), and (711/551)reflections of a face-centered cubic phase of Fd3m crystallographicspace group (Q²²⁷). Reflections are marked with the arrows in FIG. 4 a.At the SPC/GDO weight ratio of 40/60, in addition to Fd3m Bragg peaks,other reflections appear indicating different liquid crystallinestructure, i.e. different packing of the reversed micelles.

This diffraction pattern cannot be related to a single liquidcrystalline (LC) phase and can be interpreted as an intermediate phasebetween a hexagonally closed-packed reversed micellar and the cubic Fd3mphase. In general, the results show that at room temperature the phasebehavior of SPC/GDO mixtures in excess of PBS is very similar to that inexcess of water.

As also seen from FIG. 4, the effect of temperature on the nanostructureof the LC phases is lipid weight ratio-dependent (FIGS. 4 b and 4 c).Thus, at SPC/GDO weight ratio of 40/60, the LC structure remainsaffected to a minor extent. In contrast, at SPC/GDO weight ratio of30/70 the structure of the cubic Fd3m phase is very sensitive to thetemperature increase. It almost fully transforms into unorganizedreversed micellar solution (L₂) at 42° C. which is corroborated by theappearance of broad diffuse diffraction peaks showing only some distancecorrelation between reversed micelles. Only a minor portion of thesample retains Fd3m cubic nanostructure. Importantly, the cubic LC phaseformed at the SPC/GDO weight ratio of 35/65 shows moderate temperaturedependence. The temperature increase from 25° C. to 37° C. and 42° C.induces the transformation of only a fraction of the reversed micellarFd3m cubic arrangement into unorganized micelles. This is shown by thesuperimposed appearance of both Bragg diffraction peaks from cubicstructure and diffuse broad scattering from L₂ solution. The calculatedlattice parameter (a) for the Fd3m phases is relatively constant for allLC samples regardless of SPC/GDO weight ratio and temperature and onlyslightly varies between 15.1 and 15.4 nm.

FIG. 5 shows the importance of the nature of the co-solvent used toprepare lipid formulations and their ability to form ordered LCstructures upon hydration in PBS at physiologically relevanttemperatures. Here the formulations were prepared at the(SPC+GDO)/EtOH/PG weight ratios of 82/3/15, 85/10/5 and 85/15/0 and theSPC/GDO weight ratio was kept constant at 35/65. The SAXD data for allhydrated formulations at 25° C. show essentially identical diffractionpatterns of the Fd3m cubic structure. However, at increasedtemperatures, the hydrated formulation prepared using exclusively EtOHas a solvent shows lower temperature resistance.

Although it sustains more or less ordered Fd3m nanostructure at 37° C.,almost complete transformation into unordered L₂ solution is observed at42° C. In contrast, Fd3m LC phases formed from the formulations withhigh fraction of PG are much more resistant to elevated temperatures andshow stronger Bragg peaks from the cubic structure (FIGS. 5 b and 5 c).

The present Example is focused on the topical use of SPC/GDO LC phases,e.g. with solubilized benzydamine (BZD); therefore some aspects of BZDinfluence on the phase behavior of lipid mixtures have beeninvestigated. FIG. 6 summarized the SAXD data of the effect of BZD onthe nanostructure of LC phases formed in SPC/GDO mixtures as a functionof lipid weight ratio (FIG. 6 a), BZD concentration (FIG. 6 b) andformulation/PBS weight ratio (FIG. 6 c). As seen from FIG. 6 a, the BZDeffect is SPC/GDO weight ratio-dependent. Thus, at high SPC content, theeffect of 3 wt % of BZD is minimal and LC phases retain their originalnanostructure (FIG. 7). At SPC/GDO weight ratio of 30/70 this effect ismuch more prominent and the original Fd3m LC phase transforms into L₂solution at 3 wt % of BZD even at 25° C. As shown in FIG. 6 b, up to 3.5wt % of BZD can be entrapped in the cubic phase of SPC/GDO prepared atweight ratio of 35/65 without significantly altering the nanostructure.Interestingly, with increasing BZD concentration, the lattice parameterslightly increases from 15.5 to 16.6 nm as BZD concentration isincreased from 0 to 3.5 wt %. At even higher BZD concentration the cubicLC phase transforms into unordered L₂ solution. Importantly, the amountof aqueous solution needed for the formation of BZD containing LC phasesis rather small. Thus, even at a lipid formulation to PBS weight ratioof 1:1 the cubic Fd3m LC phase is formed (FIG. 6 c). Further dilution ofthe LC phase has no effect on the phase nanostructure and its unit celldimensions.

40.6—Non-Clinical Assessment of Bioadhesion and Tolerability

The current Example is focused on topical uses of bioadhesive SPC/GDO LCphases at mucosal surfaces. Hence, the importance of local tolerabilityis eminent. This aspect was investigated in three non-clinical studiesin Syrian hamsters: 1) a 7-day oral irritation study (N=24), 2) a 15-daypilot feasibility study assessing bioadhesion determining maximumfeasible dose and evaluation of local irritation (N=10), and 3) a 90-daysubchronic systemic toxicity study (N=80) of the maximum feasible dose.The 7-day study evaluated the local tolerability of SPC/GDO formulationswith and without BZD, while the pilot and the 90-days studies evaluatedSPC/GDO formulation without BZD, i.e. Episil® (Table 8). The SPC/GDOratio of the different formulations was in all cases 35/65, at which allformulations studied formed the reversed micellar (I₂) phase of Fd3mstructure (FIG. 6 b). Note, that the structure formation was notaffected by the small compositional variations between formulations,i.e. presence or absence of small amounts of BZD, peppermint oil (PMO)flavor or polysorbate 80 (P80).

TABLE 8 Composition of lipid formulations used for non-clinicalassessment of local tolerability and systemic toxicity in Syrianhamsters. SPC/GDO Study Composition (weight %) weight ratio 7-days oralirritation SPC/GDO/EtOH/PG 35/65 study 29.7/55.3/10.0/5.0 SPC/GDO/EtOH29.8/55.2/15.0 SPC/GDO/BZD/EtOH/PG 28.7/53.3/3.0/10.0/5.0SPC/GDO/BZD/EtOH 28.7/53.3/3.0/15.0 Pilot feasibility studySPC/GDO/EtOH/PG/PMO 35/65 29.47/54.73/10.0/5.0/0.05/0.75 Subchronicsystemic SPC/GDO/EtOH/PG/PMO 35/65 toxicity and local29.47/54.73/10.0/5.0/0.05/0.75 irritation study

In the 7-day study, 0.5 mL of the test formulation was applied to theleft cheek pouch daily for 7 days. The treatment generated no or minimalsigns of irritation for all 4 tested formulations.

For the 90-day study, dose selection and frequency of dosing wasdetermined in the pilot feasibility study, showing that a dose of 0.15mL given twice daily provided an apparent 24-hour exposure of the cheekpouch of Syrian hamsters to the SPC/GDO (Episil®) formulation.

In the subchronic study, it was concluded that treatment of male andfemale Syrian hamsters twice daily for 90 days with Episil® in the cheekpouches resulted in no signs of systemic toxicity or treatment relatedirritation; no test item (i.e. Episil®)-related clinical signs, and noscores of oral tissue reactions were observed in any of the animalsduring the 90 days. The test item was seen not to have any influence onthe body weight or body weight gain and no test item-related changes inhematology or clinical chemistry parameters were observed. Furthermore,the reactions identified in histopathological evaluation of the cheekpouches were considered to be mild and with no relation to the treatmentwith Episil®. There was no difference in average group irritation indexrecorded for cheek pouches treated with Episil® as compared to cheekpouches treated with sterile saline. It was concluded that twice-dailyadministration at a dose level of 0.15 ml of Episil® per treatment intoone cheek pouch for up to 90 days resulted in no signs of systemictoxicity and that Episil® was well tolerated when administered to theoral mucosal membrane. Episil® was suggested to be classified as “notirritating”.

40.7—Clinical Assessment of Intraoral Bioadhesion in Head and NeckCancer Patients

Preliminary physicochemical and functional assessments of SPC/GDO LCformulations suggested that optimal spreading and mucoadhesion coincideswith the presence of the reversed cubic micellar phase of Fd3m structureat SPC/GDO weight ratio of 35/65. The ratio for best bioadhesion wastested in a small clinical pilot study in 5 head and neck cancer (HNC)patients with a randomized crossover design featuring 4 differentformulations with SPC/GDO weight ratios of 40/60, 35/65 and 30/70, asdescribed above (See also Table 9).

TABLE 9 Composition of lipid formulations used for clinical assessmentof intraoral bio-adhesion in head and neck cancer patients undergoingradiotherapy. Treatment Composition (weight %) SPC/GDO weight ratio ASPC/GDO/BZD/EtOH/PG/PtB 35/65 28.7/53.3/3.0/10.0/5.0/0.1 BSPC/GDO/BZD/EtOH/PtB 35/65 28.7/53.3/3.0/15.0/0.1 CSPC/GDO/BZD/EtOH/PG/PtB 30/70 24.6/57.4/3.0/10.0/5.0/0.1 DSPC/GDO/BZD/EtOH/PG/PtB 40/60 32.8/49.2/3.0/10.0/5.0/0.1

The mean and median percentage presence of treatments A-D at intraoraltreatment sites over time, as visually determined by the dentalhygienist, is shown in FIG. 7.

All treatments were found to adhere well, with visual mean percentagepresence of all formulations at 8 sites in each patient exceeding 50%after 30 minutes of dosing. Notably, formulations A and B with a SPC/GDOratio of 35/65 showed the highest percentage presence at the differentintraoral sites, exceeding 50% after 3 hours. In addition, to showing anapparent maximum of intraoral coverage for the 35/65 ratio, the studyalso indicated an importance of the solvent composition, with a higherpercentage presence for the mixture of ethanol and PG compared toethanol alone. The highest median percentage coverage of intraoral sitesafter 3 h. was 87.5%, observed for formulation A.

In addition to the primary objective of the study to identify aformulation with efficient bioadhesion at the oral mucosa of patientsfor 3 h, the study also evaluated intraoral pain after dosing andpatient's subjective acceptance. Mean VAS pain scores after dosing (FIG.8) indicate that the pain after dosing was generally well managed buttended to increase with time as the protective SPC/GDO LC film was beingeroded and visually disappearing. Though formulation A appears to showthe lowest mean pain, there were no statistical differences betweentreatments. The general trend seen in FIG. 8 has been confirmed in afollow up clinical Phase II study in 38 radiation-treated HNC patients,in whom pain scores dropped to minimum values within 5 to 30 min., andthen only slowly increased over time for the subsequent 8 hours.

To assess the acceptability of the different SPC/GDO formulations,patients were asked to fill in forms regarding ease of attachment,taste, and degree of comfort. The treatments were perceived asrelatively neutral regarding taste and comfort (FIG. 9). No patientstated that formulation A was uncomfortable in the mouth, whileformulations B, C and D irritated the mouth in a few patients.Furthermore, all formulations were reported as acceptable whenadministered. Most of the formulations took less than 1 minute to form agel, with formulation A showing the fastest time to gel formation. Allformulations met the requirement of suitability for further clinicaldevelopment, the best suited being formulation A with the SPC/GDO ratioof 35/65 and containing 10 wt % ethanol and 5 wt % PG. This ratio waschosen for further clinical development of the Episil® medical deviceproduct for the treatment of intraoral pain e.g. in patients with oralmucositis, now registered in EU and US.

40.8—Drug Delivery Aspects of SPC/GDO LC Formulations

One of the important aspects of long-acting formulations is the abilityto incorporate relevant amounts of pharmaceutical active ingredients(APIs) and to control their release in vivo, e.g. by retaining thedesired cubic nanostructure. We investigated the effect of threeselected active pharmaceutical ingredients (APIs), lidocaine (LID),triamcinolone (TCA), and granisetron (GRN), on the nanostructure of theFd3m cubic phase formed upon hydration of the (SPC+GDO)/EtOH/PGformulation prepared at 85/10/5 weight ratio (FIG. 10). The SPC/GDOweight ratio of 35/65 was kept constant for all formulations.

As shown from FIG. 10 a, the formation of the cubic Fd3m phase was notsignificantly affected by the presence of LID up to a concentration of1.7 wt %. At 2 wt % of LID the ordered cubic structure began totransform into L₂ solution. The calculated lattice parameter onlyincreased slightly from 15.5 to 16.1 nm when LID concentration wasincreased from 0 to 2 wt %. At a LID concentration slightly lower than 3wt % the cubic structure was completely lost and the LC phasetransformed into unordered L₂ solution. The entrapment of rather largeamounts of TCA showed very little effect on both the formation andlattice dimensions of the cubic structure of the formulation (FIG. 10b). At even 5 wt % of TCA the Fd3m structure remained unaltered. TheFd3m cubic structure of the hydrated formulation was found to be verysensitive to the presence of GRN (FIG. 10 c). At only 0.8 wt % of GRNthe superimposed diffuse scattering from L₂ solution first appeared andat about 1.5 wt % of GRN the cubic structure completely disappeared. Thestrong disordering ability of GRN was followed by its influence on thecubic phase unit cell dimensions. Hence, when GRN concentration wasincreased from 0 to 1 wt % the lattice parameter increased from 15.5 to16.6 nm. Note, that a very similar effect was also observed in the caseof BZD (FIG. 6 c).

It may be concluded that all studied APIs have common, albeit relativelysmall, disordering effect on the nanostructure of hydratedSPC/GDO/EtOH/PG formulation. The formulation can generally accommodateamounts of the 3 APIs at levels that are predicted to be therapeutic ifcompared with registered pharmaceutical products. The collectiveobservation is that with increasing API concentration the latticeparameter of the Fd3m cubic phase increases to about 16.6 nm, beforetransforming into the L₂ phase. Most likely further unit cell dimensionand accommodation increase of the guest molecule is not possible withoutstructural changes, due to the complex cubic packing constraints withinthe LC structure. After the maximum load of the API is reached, furtherconcentration increase causes transformation of the Fd3m cubic structureinto unordered L₂. This is a topic for further studies and clinicaltrials.

40.9—Conclusions

Data from Example 40 show that lipid liquid crystal-forming systems ofSPC and GDO effectively adhere at mucosal surfaces in the oral cavityfor extended periods of time. Adherence periods are demonstrated to beat least 3 hours post-dosing. This is seen in the clinical pilot studyin Head and Neck Cancer patients. The best coverage and overallacceptability was observed for a SPC/GDO ratio of 35/65 but other testedcombinations provided coverage for extended periods also. The 35/65SPC/GDO ratio coincides with the formation of a reversed cubic micellarI₂ phase of Fd3m structure.

The topically administered bioadhesive SPC/GDO 35/65 formulations arewell tolerated locally and systemically when administered twice dailyfor up to 90 days. This was demonstrated by extended non-clinicalstudies in Syrian hamsters.

The present study furthermore explored the influence of added APIs onthe phase structure of SPC/GDO compositions. It was concluded in thesestudies that significant amounts of API with widely differentphysicochemical properties can be added to the lipid phase withoutsignificantly altering the phase behavior.

The APIs benzydamine, lidocaine, triamcinolone and granisetron werechosen as typical examples. They represent a structurally diverse groupof active agents but are relevant for intraoral topical application. Alltested active agents can be adminstered at clinically relevantconcentrations using at dosage volumes well below the studies' maximumdose. It is also seen that increased concentrations of API can beobtained while maintaining structural integrity of the lipidcomposition. This can be achieved by tuning the lipid composition, tocompensate for the API's effect on the phase behavior. In conclusion,the SPC/GDO system, shows great promise for a wide range of medicalapplications involving administration of an API to a body surface.

LEGENDS TO FIGURES

FIG. 1. Cumulative release of MB from a depot forming a reversedhexagonal H₁₁ phase.

FIG. 2. Decrease in viscosity of the depot precursor on addition ofsolvents. PC/GDO (6/4) is a precursor to a reversed hexagonal H_(II)phase and PC/GDO (3/7) is a precursor to a reversed cubic I2 phase.

FIG. 3: Release of Chlorhexidine from formulation A, see Example 33.

FIG. 4. SAXD profiles of SPC/GDO mixtures in excess PBS as a function oflipid weight ratio at 25 (a), 37 (b), and 42° C. (c) prepared at lipidformulation:PBS weight ratio of 1:2. Arrows in (a) show indexing of thereflections from the reversed micellar Fd3m cubic phase. Explanation isgiven in the text.

FIG. 5. SAXD profiles of SPC/GDO/EtOH/PG formulations in excess PBS as afunction of EtOH/PG weight ratio at 25 (a), 37 (b), and 42° C. (c)prepared at lipid formulation:PBS weight ratio of 1:2. SPC/GDO weightratio is 35/65 for all samples.

FIG. 6. Effect of 3 wt % of BZD on the liquid crystalline nanostructureas a function of SPC/GDO weight ratio at lipid formulation:PBS weightratio of 1:2 (a). Effect of BZD concentration on the nanostructure ofSPC/GDO liquid crystalline phases prepared at weight ratio of 35/65 (b).Effect of 3 wt % of BZD on the liquid crystalline nanostructure as afunction of lipid formulation:PBS weight ratio at SPC/GDO weight ratioweight ratio of 35/65 (c). The lipid/EtOH/PG weight ratio was 85/10/5for all samples.

FIG. 7. Time dependence of the mean (±SD) (a) and median (b) values ofpercentage of sites where treatment was present after administration ofSPC/GDO/BZD/EtOH/PG formulations prepared at weight ratios of53.3/28.7/3/10/5 (A), 53.3/28.7/3/15/0 (B), 57.4/24.6/3/10/5 (C), and49.2/32.8/3/10/5 (D). Number of examined sites in mouth=8 (left andright sides of the upper palate, lower palate, inside of the cheek andtongue), number of patients=5.

FIG. 8. Time dependence of the mean VAS score after administration oflipid formulation. Patient question form: evaluation of the analgesiceffect (pain in mouth). Visual analog scale (VAS): 0=no pain, 100=worstimaginable pain. SPC/GDO/BZD/EtOH/PG formulation compositions by weightare: 53.3/28.7/3/10/5 (A), 53.3/28.7/3/15/0 (B), 57.4/24.6/3/10/5 (C),and 49.2/32.8/3/10/5 (D). Number of patients=5.

FIG. 9. Patient reported outcomes regarding taste (a) degree of comfort(b) after dosing of lipid formulations to head and neck cancer patients.Formulation compositions by weight are: 53.3/28.7/3/10/5 (A),53.3/28.7/3/15/0 (B), 57.4/24.6/3/10/5 (C), and 49.2/32.8/3/10/5 (D).Number of patients=5.

FIG. 10. Effect of lidocaine (a), triamcinolone (b), and granisetron (c)on the nanostructure of SPC/GDO/EtOH/PG liquid crystalline phases. Theformulation:PBS weight ratio was 1:2, the SPC/GDO weight ratio was 35/65and lipid/EtOH/PG weight ratio was 85/10/5 for all samples. Theconcentration of API is expressed as wt % of the total formulationweight.

1. A pre-formulation comprising a low viscosity mixture of: a) at leastone neutral diacyl lipid and/or a tocopherol; b) at least onephospholipid; c) at least one biocompatible, organic solvent; includingat least one bioactive agent is dissolved or dispersed in the lowviscosity mixture, wherein the pre-formulation forms, or is capable offorming, at least one liquid crystalline phase structure upon contactwith an aqueous fluid and/or body surface.
 2. A pre-formulation asclaimed in claim 1 wherein said liquid crystalline phase structure isbioadhesive.
 3. A pre-formulation as claimed in claim 1 whereincomponent a) consists essentially of diacyl glycerols.
 4. Apre-formulation as claimed in claim 1 wherein component b) isphosphatidylcholine.
 5. A preformulation as claimed in claim 1 having aviscosity of 0.1 to 5000 mPas.
 6. A preformulation as claimed in claim 1having a molecular solution, L₂ and/or L₃ phase structure.
 7. Apreformulation as claimed in claim 1 having 35 to 60% by weight a), 20to 50% by weight b) and 10 to 20% by weight c).
 8. A preformulation asclaimed in claim 1 wherein component c) is an alcohol.
 9. Apreformulation as claimed in claim 1 additionally comprising up to 10%by weight of a)+b) of a charged amphiphile.
 10. A preformulation asclaimed in claim 1 wherein said active agent is selected fromcorticosteroids, nonsteroidal anti-inflammatory compounds, localinhibitors of inflammatory pathways phospholipase inhibitors,antioxidants, antiinfectives, cytokines and cytokineinducers/supressors.
 11. A preformulation as claimed in claim 1 whereinsaid active agent is a corticosteroid.
 12. A preformulation as claimedin claim 11 wherein said active agent is at least one hydrocortisonetype (Group A), acetonide type (Group B), betamethasone type (Group C),or ester type (Group D) corticosteroid.
 13. A preformulation as claimedin claim 1 wherein said active agent is at least one selected from thegroup consisting of hydrocortisone, hydrocortisone acetate, cortisoneacteate, tixocortol pivalate, prednisolone, methylprednisolone,prednisone, triamcinolone acetonide, triamcinolone alcohol, mometason,amcinonide, budesonide, desonide, fluocinonide, fluocinonide acetonideand halcinonide.
 14. A preformulation as claimed in claim 1 which isadministrable by rinsing, spraying, gargling, as a patch, by suppositoryor by enema.
 15. A preformulation as claimed in claim 14 comprisingbenzydamine or triamcinolone
 16. A topical preformulation as claimed inclaim 1 suitable for intraoral administration which forms a bioadhesive,controlled release product, wherein said bioactive agent comprises atleast one selected from; benzydamine, triamcinolone, tramadol,Acetaminophen, Ibuprofen, Propoxyphene, Codeine, Dihydrocodein,Hydrocodone, Oxycodone, Nalbuphine, Meperidine, Leverorphanol,Hydromorphone, Oxymorphone, Alfentanil, Fentanyl and Sefentanil.
 17. Atopical preformulation as claimed in claim 1 suitable for intraoraladministration for treatment of periodontal and topical infections,wherein the active agent is chlorhexidine gluconate, and where thepreformulation is applied as a liquid product which forms a surface gelin situ between 1 second and 5 min after application.
 18. A topicalpreformulation as claimed in claim 1 suitable for ocular administration,wherein said active agent comprises at least one selected fromdiclofenac, pilocarpine, levocabastine hydrochloride, ketotifenfumarate, timolol, betaxolol, carteolol, levobunolol, dorzolamide,brinzolamide, epinephrine, dipivefrin, clonidine, apraclonidine,brimonidine, pilocarpine, atanoprost, travoprost, bimatoprost,unoprostone, pilocarpine hydrochloride, dexamethasone, chloramphenicol,indomethacin and triamcinolone.
 19. A topical preformulation as claimedin claim 1 for dermatological administration which forms a bioadhesive,controlled release product, wherein the active agent is selected fromcosmetic agents, fragrances, flavourings, essential oils UV absorbingagents and mixtures thereof.
 20. A method of delivery of a bioactiveagent to a human or non-human animal body, this method comprisingadministering a pre-formulation comprising a non-liquid crystalline, lowviscosity mixture of: a) at least one neutral diacyl lipid and/or atleast one tocopherol; b) at least one phospholipid; c) at least onebiocompatible, oxygen containing, low viscosity organic solvent; and atleast one bioactive agent is dissolved or dispersed in the low viscositymixture, whereby to form at least one liquid crystalline phase structureupon contact with an aqueous fluid in vivo following administration. 21.A method of treatment or prophylaxis of a human or non-human animalsubject comprising administration of a preformulation as claimed inclaim
 1. 22. A method for the treatment of a human or animal subjectcomprising administration of a preformulation as claimed in claim
 1. 23.A method as claimed in claim 22 for the treatment of inflammation and/orirritation at a body surface and/or in a body cavity.
 24. A method asclaimed in claim 23 wherein said inflammation is caused by Crohn'sdisease, ulcerative collitus or oral mucositis.
 25. A method for thetreatment of oral mucositis in a human or animal subject comprisingadministration of a preformulation as claimed in claim 1, saidcomposition comprising 40 to 60 wt % GDO, 20 to 35% PC, 5 to 25%ethanol, and 1 to 8% benzydamine or triamcinolone, or a derivativethereof.